# w12 overheating



## 73blazer (Feb 19, 2020)

I'm just driving home from a business trip 230mi and it's 82f out and the coolant temp kept.rising almost to red. I opened the windows and turned the heat on and it dropped it a bit but the. keept creeping up. I checked the coolant when I got it it was a touch below the min mark I topped off with g13 with the idea of changing the coolant sometime soon as it has 113k mi and unknown history. . It did this once while on the trip too when it was 90f but I only drive 20mi back and forth from my customer to where I was staying. . And the whole way down it was 85f and no problems. It has also been going to 200 within 5mins of turning it on and driving 30mph out the side roads.....but ive no experience with whats normal with this car. I know it didnt do that when it was 40f out. Recommendations on what to check? .


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## Phat One (Jul 10, 2009)

1 Stuck thermostat?
2.Bad coolant sensor?


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## 73blazer (Feb 19, 2020)

Well conventional wisdom says thermostat. But if there's one thing I learned about this car, conventional wisdom, doesn't generally apply. 
That said, the fact that I can turn on the heater and it drops or at least maintains, tells me, not enough coolant is getting cooled or through the main radiator. 

I stopped a few times on the rest of the way home, the last time I hooked up the VCDS which I had with me. Both sensors (I'm assuming those are the readings in 01 and 11 engine modules?) read the same, which match the dash gauge more or less. The last time I stopped was for 2 hours at a cigar lounge when I came out I hooked it up and coolant read 81c. Started it up, within 1-2 mins it was at 95. it held 95 for 20 minutes driving 72mph with ambient outside at 65 and falling. After about 30miles, it started climbing ever so slowly. It reached 116c and kinda leveled off, I hadn't turned the heater on in that instance, yet. It held 116c for another 20-30mi then started climbing a little whle the outside ambient was dropping, so I turned the heater on full blast and it dropped to 95c instantly. I did log that hour and half or so. I'll check that log out in the morning. 

By the time I got home it was 58F ambient outside and coolant temp was still climbing ever so slow if I didn't have the heater on. I know I drove it a few months ago for several hundred miles in similar temp and it did not exhibit that issue. So, this is new. Considering both sensors read the same, I checked the coolant it's full up, not dropped any since I topped off 3kmi ago when I first bought it, I also had checked it I dipped a rag in and rang it out in a clear plastic cup, while I'm not the best at color, it looked like G12+/++ or G13 to me. I am leaning to thermostat, but...who knows. Now that I can do research on a real computer and not my phone, I'll check out what I might diag next to hone in on the issue before I throw parts at it.


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## invisiblewave (Sep 22, 2008)

You might try idling it for a while on a slope with the coolant cap off, with the tank at the highest point, just in case there's any air in the system.


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## 73blazer (Feb 19, 2020)

Well I can certainly try that. But it was fine a month ago and i've not opened the coolant system until the problem occured to check the level. 

Here's the graph from the logged VCDS data from the last part of my trip. This is pretty much set on cruise on mostly flat roads at 70mph over about an hour and half. . The blip in the graph is when I turned the heater on, it held for a little while and started creeping up even with the heater on and outside ambient falling from about 72 at the beginning of that graph to 58 or so at the end. Earlier in that trip, before the VCDS data, it would just keep going up past 140c and near the red and I'd pull off and let it sit for a bit. 
The latter part of the graph is me driving 45mph on side roads to get the rest of the way to my house
It definitely seems to me that not enough coolant is getting cooled/circulated through the main radiator.


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## 73blazer (Feb 19, 2020)

I found an older post that shows much better MVB to monitor:





53PL-50AAA-VW611BAN said:


> Now for the ones you really want:
> Controller #1
> Display Group 130 shows:
> 
> ...


So I'll watch those on a test run and see what they do.


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## Phaetonlvr (Feb 26, 2013)

I was just about to post the link to that recent thread. The electronically controlled thermostat on the W12s is somewhat known to fail, two of mine had it replaced before I got them. 

Definitely monitor both temp sensors and also monitor the cooling fans. If you do end up having to replace the thermostat I'd recommend putting in new spark plugs at the same time or at least pulling the plugs and making sure there's no oil sitting in the spark plug wells. If you see oil then be prepared to put new valve cover gaskets on it which at that point, with the intake manifold removed, is actually not that much work.


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## PowerDubs (Jul 22, 2001)

At that point, check your coil pack part #s... early ones like to fail, sometimes taking the car with it.

https://youtu.be/hYoXNWPAjIM


Sent from my iPhone using Tapatalk


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## PowerDubs (Jul 22, 2001)

Btw- I wouldn’t play with overheating this engine. All aluminum, and if you warp something- might as well junk the car. 


Sent from my iPhone using Tapatalk


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## Phaetonlvr (Feb 26, 2013)

PowerDubs said:


> At that point, check your coil pack part #s... early ones like to fail, sometimes taking the car with it.


You can call the VW Touareg & Phaeton Customer Care Hotline at 1-877-742-3866 to find out if the Ignition Coil Recall has been done on your car, they have the records. They can also tell you the in-service date in case you are curious.


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## 73blazer (Feb 19, 2020)

I dont play with overheating any engine. Even a SBC. Overheating any engine is a death sentence. 
It approached 130C or so and I shut it down. running 120 may be a bit on the edge, but you know, i gotta get home. I'm going by the designers thresholds. While I don't like 120 or 130, "red" is 150c or so, i never got any messages or even a check engine light or faults that don't trip the light... and performance never seemed to waiver. I think it's ok. But it needs fixed, for sure. so much for running 186 for 24hrs . That said, my gut guess is, it was running purely on the aux radiator which from what I seem to read is always circulating, so it's over engineering may have gotten me home.


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## snapdragon (Aug 8, 2006)

https://www.flyingspares.com/shop/b...s-from-2012-on/water-pump-w12-07d121008b.html
Could the plastic impeller on the main waterpump have sheared off the shaft - I have had this before on a BMW? Does the radiator get hot ?


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## 73blazer (Feb 19, 2020)

snapdragon said:


> https://www.flyingspares.com/shop/b...s-from-2012-on/water-pump-w12-07d121008b.html
> Could the plastic impeller on the main waterpump have sheared off the shaft - I have had this before on a BMW? Does the radiator get hot ?


Yeah I considered that. I'm not quite sure how the symptoms would vary from a t-stat that won't open or will only partially open versus a water pump impeller that is not longer spinning. I would think no circulation at all would overheat instantly? But then there's that aux water pump, I'm not sure how the main and aux interact or what their roles really are. 
For sure I'm getting some cooling somewhere or it would just instantly keep going up, the fact that it can maintain albeit a somewhat higher than it should be temp, with the heater on and I get heat the whole time...says some coolant is circulating somewhere. I'll do those MVB today, that will at least help diag what it could be.

That said, the fact that an impeller can come off the shaft is pretty crappy engineering. While I've not much experience with non-US vehicles, I've done plenty of water pumps on Chrysler/Ford/GM vehicles where bearings or seals were failed, but an impeller coming off it's shaft? That seems...wrong.


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## 73blazer (Feb 19, 2020)

Definitely getting worse. 
20 min trip to get some take out and 20 min back...

This time as I was pulling back in the drive 200' from my garage I got a "coolant overheating" message on the DIC. 


Here's the data from block 130 over a 40min trip. I have 135 and 136 too but nothing interesting there and they don't flow on this graph without some excel magic for 1/2hr which I don't feel like doing. Suffuce it to say I was doing 55-70mph anyway so fans not required. I did not have the heater on, in fact I turned the A/C to full low the whole time to attempt to produce the problem, which worked. Ambient outside temp was about 72F. 

Dash showed almost near the red when I pulled in the drive at the end. So that's what 140-150c nominal engine coolant temp? I didn't have the engine coolant temp from group 1 logged so it's no in the graph, but she was going nothing but up!










What's this really showing? Dash went to 200F and stayed for most of the trip there. then starting creeping up on the way back. The fact that they are diverging towards the end and t-stat duty keeps going up toward the end rather says to me that the t-stat isn't actually opening at least after the engine gets nice and warm. I dunno..
YOu can clearly see the t-stat opening and the rad coolant output increasing on the graph though in the beginning which says the t-stat can work at some level.... What happens later???? Mabey t-stat doesn't work when the heat actually soaks into it for real??? Car's full of data!

Unless I'm reading this wrong, it seems to me the calls to t-stat aren't having much effect beyond the first call, and clearly in the end the lines are diverging. I'm heavily leaning bum t-stat at this point.


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## 73blazer (Feb 19, 2020)

Phaetonlvr said:


> You can call the VW Touareg & Phaeton Customer Care Hotline at 1-877-742-3866 to find out if the Ignition Coil Recall has been done on your car, they have the records. They can also tell you the in-service date in case you are curious.


BTW, this number no longer in service. Well, it's in service, but it's a recording that says, we don't recognize you as special anymore, call the regular VW customer care #. 

If you call the regular VW customer care, if you pick anything other than TDI settlement option or roadside assistance option, you get a recording that says they are in an all office meeting. Haha...that's funny.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

My dealer showed me the coil pack recall paperwork on my Phaeton. They weren't the original dealer. 

I didn't even know there was a coil pack recall until they showed me they had been replaced under the recall.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

Are the radiator fans coming on?


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## invisiblewave (Sep 22, 2008)

53PL-50AAA-VW611BAN said:


> My dealer showed me the coil pack recall paperwork on my Phaeton. They weren't the original dealer.
> 
> I didn't even know there was a coil pack recall until they showed me they had been replaced under the recall.


I had two fail before the recall and paid to have all 8 changed. When the recall happened, VW sent me a check.


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## 73blazer (Feb 19, 2020)

Yes, both fans work. BUt fans not needed when doing anything over 45 mph. More CFM is pushed the rad at anything above 30-40mph than any fan could hope to do. All my driving is highway/backroads. If I see two lights in 200 mi, that's alot and my avg speed is is well over 40mph. That's why I wanted this car, perfect road machine!


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## Phaetonlvr (Feb 26, 2013)

73blazer said:


> What's this really showing? Dash went to 200F and stayed for most of the trip there. then starting creeping up on the way back. The fact that they are diverging towards the end and t-stat duty keeps going up toward the end rather says to me that the t-stat isn't actually opening at least after the engine gets nice and warm. I dunno..
> YOu can clearly see the t-stat opening and the rad coolant output increasing on the graph though in the beginning which says the t-stat can work at some level.... What happens later???? Mabey t-stat doesn't work when the heat actually soaks into it for real??? Car's full of data!
> 
> Unless I'm reading this wrong, it seems to me the calls to t-stat aren't having much effect beyond the first call, and clearly in the end the lines are diverging. I'm heavily leaning bum t-stat at this point.


My guess would also be the thermostat not opening correctly. I'd assume that the MVB for t-stat duty cycle is showing the commanded position and not the actual position. Not sure if the t-stat has the capability to show actual position. 

I haven't read through the few t-stat failure threads in a while. I think there was a fault code but maybe that's just for total failure. Maybe worth reading up on.


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## PowerDubs (Jul 22, 2001)

73blazer said:


> More CFM is pushed the rad at anything above 30-40mph than any fan could hope to do.




That's pure speculation.



So I'll speculate the other way-

I think it is pretty easy to think otherwise. Just like a head wind or tailwind makes a difference even at highway speed.

I'd wager that the fans already pulling air through the radiator and shoving it into/out of the engine bay makes 'room' for even more air than would come in from just road speed alone.

Think of it this way- you have a given volume of air hitting the front of the car at a given speed, say 60mph. If it can't get into the rad quick and easy- it will 'pile up' and go around up over the hood or under the car. Make it easier for it to get in- and it will.


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## Phaetonlvr (Feb 26, 2013)

73blazer said:


> BTW, this number no longer in service. Well, it's in service, but it's a recording that says, we don't recognize you as special anymore, call the regular VW customer care #.
> 
> If you call the regular VW customer care, if you pick anything other than TDI settlement option or roadside assistance option, you get a recording that says they are in an all office meeting. Haha...that's funny.


A few years ago they changed it to just being a Touareg line but would still work with Phaeton customers. Last summer was the last time I called when I bought the latest W12 in my fleet. I'm sure regular VW customer care will be able to tell you also ... if you can get them to answer.


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## Phat One (Jul 10, 2009)

The thermostat has no electrical connectors s cannot send any information about it's open/closed position. If it's anything like the V8, the thermostat has a small hole in it that will allow a slow passage of coolant at all times. As for the coil packs, most dealerships will place a sticker on the underside of the hood to show that a recall was done.

Graham


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

W12 MAP controlled Thermostat thread from the FAQ:

https://forums.vwvortex.com/showthread.php?2993477


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## 73blazer (Feb 19, 2020)

PowerDubs said:


> That's pure speculation.
> 
> 
> 
> ...


While I totally recognize your value here and very much respect your opinions, and I know I'm new here.......on this one, i simply have to say no. No speculation. While building my 73blazer from the ground up I asked several OEM engineers (my customers are ford,gm,honda,Chrysler..yeah I do IT work, but I also build and maintain cars) about his very thing as I didn't want the nasty clutch fan of old and too much coverage on elec fans can be in impediment. Everyone told me, and do the math, that (of course depending a little on vehicle grille openings and such) once over 30-40mph your pushing far more air through the radiator than any fan can hope to accomplish and in fact the fans become an impediment to air flow so much so they design fan blades to be less of an impediment while off and spinning freely through the air more so than they design them to move air when on. One hard truth, fans are only there to provide airlfow at low or no speed perioid. You can see this in fact with the Phaeton, once over 30mph or so the fans will no operate, no matter how hot it gets.Watch the group 135, as soon as you get up to a certain speed, fans off. The engineers programmed it that way because the fan at speed is a determent. But they both work as soon as your at light or stopped or muttling along in stop an go traffic, which thankfully is a rarity for me.


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## invisiblewave (Sep 22, 2008)

73blazer said:


> While I totally recognize your value here and very much respect your opinions, and I know I'm new here.......on this one, i simply have to say no. No speculation. While building my 73blazer from the ground up I asked several OEM engineers (my customers are ford,gm,honda,Chrysler..yeah I do IT work, but I also build and maintain cars) about his very thing as I didn't want the nasty clutch fan of old and too much coverage on elec fans can be in impediment. Everyone told me, and do the math, that (of course depending a little on vehicle grille openings and such) once over 30-40mph your pushing far more air through the radiator than any fan can hope to accomplish and in fact the fans become an impediment to air flow so much so they design fan blades to be less of an impediment while off and spinning freely through the air more so than they design them to move air when on. One hard truth, fans are only there to provide airlfow at low or no speed perioid. You can see this in fact with the Phaeton, once over 30mph or so the fans will no operate, no matter how hot it gets.Watch the group 135, as soon as you get up to a certain speed, fans off. The engineers programmed it that way because the fan at speed is a determent. But they both work as soon as your at light or stopped or muttling along in stop an go traffic, which thankfully is a rarity for me.


I agree, he's talking a load of old bollocks!:laugh:


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## 73blazer (Feb 19, 2020)

I did find this from SSP222


SSP222P21 said:


> The fan does not cut in at road
> speeds above 100 kph, because
> the fan does not provide additional
> cooling at speeds higher
> than this.


That's a general guide not specific to the Phaeton, just VW's general map controlled t-stat cooling systems but SSP250 which is W12 specific shows road speed as an input to the fan control. 

Anyway, suffice it to say, the fans both do work, in addition to hearing them I visually put my eyes on them both spinning. 

I'm still guessing thermostat. I suppose it could be a bum sensor, but the data seems to better indicate t-stat or possibly a water pump failure. 
I did find SSP250 that explains the function of the 2ndary water pump. It basically says it's there to provide some addition flow during low RPM in case the main pump isn't doing enough RPM, and to provide run-on after you shut the car off. Given that I have extreme hot heat constantly when I turned the heater on during the rise, I'm gonna guess my main pump is ok, I don't think the 2ndary pump would provide enough circulation to give a constant extreme heat like that and I think it would be overheating very quickly, not slowly like mine does, if the main pump was out.


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## 73blazer (Feb 19, 2020)

Here's a question Controller#1 group 136 has an "aux pump status" but the field is blank, there's no value displayed there ever. 

I know these cars at least in ROW could be fitted with a true battery powered aux pump/heater to heat the coolant prior to starting so I'm not sure if that display is for that, or the V51 "continued circulation pump" or what. 
Is that value supposed to be blank, if others see a value there then perhaps my aux pump is not responding or offline??


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## Phaetonlvr (Feb 26, 2013)

73blazer said:


> Here's a question Controller#1 group 136 has an "aux pump status" but the field is blank, there's no value displayed there ever.
> 
> I know these cars at least in ROW could be fitted with a true battery powered aux pump/heater to heat the coolant prior to starting so I'm not sure if that display is for that, or the V51 "continued circulation pump" or what.
> Is that value supposed to be blank, if others see a value there then perhaps my aux pump is not responding or offline??


Here's what one of my '04 W12s shows (with ignition on, engine off):


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## PowerDubs (Jul 22, 2001)

73blazer said:


> Yes, both fans work. *BUt fans not needed when doing anything over 45 mph. More CFM is pushed the rad at anything above 30-40mph than any fan could hope to do*.






Reading.







PowerDubs said:


> That's pure speculation.





Replying.




73blazer said:


> While I ....,* i simply have to say no. No speculation*. .....*Everyone told me, and do the math*, that (of course depending a little on vehicle grille openings and such) *once over 30-40mph your pushing far more air through the radiator than any fan can hope to accomplish* _* One hard truth*_, fans are only there to provide airlfow at low or no speed perioid.




Raised eyebrow.







invisiblewave said:


> I agree, he's talking a load of old bollocks!






Am I?









73blazer said:


> SSP222P21
> The fan does not cut in at road
> speeds above 100 kph, because
> the fan does not provide additional
> ...






*100kph over 62MPH*..... not 30-40, not 45. BIG difference. :wave::beer:


Holy hell- 'engineers' from Ford, GM, Honda, Chrysler.... only one of those companies is respectable, and more so for their motorcycles and racing than modern cars. None have ever built engines anywhere near the technology and complexity that VW has time and time again.


Might as well say I can fix a lawn mower, and work at AutoZone. I have an awesome set of tools. At my apartment.


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## 73blazer (Feb 19, 2020)

PowerDubs said:


> Reading.
> 
> 
> 
> ...


Well hey, I'm not disputing your disposition. But, my 200kmi 20 year old GM cars don't overheat with nothing more than a coolant change. . I'm just trying to get my Phaeton back where I can use it instead of sitting in the garage doing nothing being unsuable. Friendly argument on the fans purpose asideopcorn::beer::beer:, both fans do operate. So what is it, thermostat? Pump? What more can I trace to narrow in on the problem. I'm about ready to just buy a t-stat and the related $$$$ intake gaskets to try it. While I'm under the intake I'll change the sparks and valve cover gaskets for fun due to my occasional efficiency below threshold problem on one bank. But, being the t-stat and intake gaskets are ~$500, i'd like to try to pinpoint the issue if it's possible before I throw parts at it. . I'm pretty sure there's coolant flow at least from one pump as I get super hot heat in the cabin as it's rising, so it's moving thru there at least.


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## 73blazer (Feb 19, 2020)

Phaetonlvr said:


> Here's what one of my '04 W12s shows (with ignition on, engine off):


Hmm...this is interesting. I don't get any value in 136-3. LIke it's not there. 
I dunno though, the aux pump as I read in the SSP should only supplement the main pump at low speed. Would a non-working aux pump while the main was working lead to overheating at moderate speed (45-70mph)? Very interesting.
I did get a value in after-run coolant and after I switched the engine off but still had the ign. on, it moved from OFF to After-Run.



vcds trace said:


> OFF
> OFF
> OFF
> OFF
> ...


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

I have the Phaeton W12 Engine Management System Design and Function SSP 892303 hard copy.

It says this about the Map Operated Thermostat under the heading "Effects of Failure" (summarized below):

If there is no operating voltage present, the large cooling circuit is opened by the wax thermocouple in the thermostat.

It opens at 230 degrees F / 110 degrees C and the fans come on. 

There is a map which takes into account car speed but it looks like 110 Degrees C is the magic temp where the fans are supposed to come on. 



The after-run pump comes on at low engine speeds depending on engine speed and coolant temperatures (the SSP doesn't say what engine speed or coolant temperature). It does mention that it's so there is adequate coolant circulation even in stop and go traffic. 

The next paragraph says it comes on after the engine is shut off depending on coolant temperature at the radiator and engine outlets, the engine oil temperature and the intake air temperature. 

To prevent it from seizing up, it comes on for approximately 5 seconds each time the engine is started.

It sounds like your after-run pump is doing what it's designed to do (unless the engine was idling and the coolant temperature was high enough to turn it on before you shut off the engine).



The Map-Controlled thermostat and the after-run pump are both controlled by the Map in Engine ECU 1. 

Even if Engine ECU 1 has no faults, you could try clearing faults in it to see if it needs a reset. 

Resetting Engine ECU 1 probably won't work but it's free.

The only downside is that the readiness will need to be set again. You will have to drive it if you need the readiness set. None of the W12 set readiness tricks have worked on either of my Phaetons.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

Hmm, my hard copy of the SSP doesn't even mention the Auxiliary Coolant Pump. 

I will check the relay and fuse .pdf to see what it says.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

53PL-50AAA-VW611BAN said:


> Hmm, my hard copy of the SSP doesn't even mention the Auxiliary Coolant Pump.
> 
> I will check the relay and fuse .pdf to see what it says.


I searched the .pdf for "pump".

Fuse SD6 protects the Aux Coolant Pump J496. It also protects the After-Run Pump V51, the SAI Pump and the relay for Fuel Pump 2. It also protects V36 which the SSP says is the main coolant pump for the W12 but this .pdf says it's for Engine Code BGJ.

The relay for the Aux Pump J496 is a 404 relay like the fuel pump relays and it's at position 1A in the right footwell.

Fuse SB30 protects Coolant Pump V50 and it's in the fuse box under the steering wheel. This is part of the HVAC, but is in the pump that transfers coolant from the engine to the HVAC system. 

Fuse SB65 protects the "Recirculation Pump" V55 which I don't see in the Engine or the HVAC study guides.

If you have the Bentley repair manual, it shows some component locations.


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## 73blazer (Feb 19, 2020)

53PL-50AAA-VW611BAN said:


> I have the Phaeton W12 Engine Management System Design and Function SSP 892303 hard copy.
> 
> It says this about the Map Operated Thermostat under the heading "Effects of Failure" (summarized below):
> 
> ...





53PL-50AAA-VW611BAN said:


> Hmm, my hard copy of the SSP doesn't even mention the Auxiliary Coolant Pump.
> 
> I will check the relay and fuse .pdf to see what it says.





53PL-50AAA-VW611BAN said:


> I searched the .pdf for "pump".
> 
> Fuse SD6 protects the Aux Coolant Pump J496. It also protects the After-Run Pump V51, the SAI Pump and the relay for Fuel Pump 2. It also protects V36 which the SSP says is the main coolant pump for the W12 but this .pdf says it's for Engine Code BGJ.
> 
> ...




Wow, thanks for all that detailed info. There's alot there. 
I did a pressure check on the system last night, that held 18lbs for hours, no problems. So, it's not leaking.


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## MamboMedic (Nov 14, 2010)

VCDS is great for lots of stuff but cooling issues are not usually one of them at least in my experience. 
Do the fans run at both high and low speeds?
Do the fans kick on high when you turn on ac?
Does the temp drop while driving with ac on?
The Phateon is at the age where most VW’s start to have cooling issues. Are the upper and lower hoses under pressure? Is there a temp difference between them? Has the cap been pressure tested? Has the system been pressure tested? I’ve gone crazy with this issue and will finally find a tiny pinhole. The small ones prevent the system from getting to proper pressure without noticeable coolant loss. Is the water pump plastic or metal impelers? I’ve gone crazy before pulling pump and finding it can’t push coolant.


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## kirk_augustin (Jul 21, 2012)

73blazer said:


> While I totally recognize your value here and very much respect your opinions, and I know I'm new here.......on this one, i simply have to say no. No speculation. While building my 73blazer from the ground up I asked several OEM engineers (my customers are ford,gm,honda,Chrysler..yeah I do IT work, but I also build and maintain cars) about his very thing as I didn't want the nasty clutch fan of old and too much coverage on elec fans can be in impediment. Everyone told me, and do the math, that (of course depending a little on vehicle grille openings and such) once over 30-40mph your pushing far more air through the radiator than any fan can hope to accomplish and in fact the fans become an impediment to air flow so much so they design fan blades to be less of an impediment while off and spinning freely through the air more so than they design them to move air when on. One hard truth, fans are only there to provide airlfow at low or no speed perioid. You can see this in fact with the Phaeton, once over 30mph or so the fans will no operate, no matter how hot it gets.Watch the group 135, as soon as you get up to a certain speed, fans off. The engineers programmed it that way because the fan at speed is a determent. But they both work as soon as your at light or stopped or muttling along in stop an go traffic, which thankfully is a rarity for me.


Yes, I tend to agree that at highway speeds, fans should be irrelevant.
But don't ignore the bizarre.
For example, a rattling idler bearing can cause the knock sensor to retard the ignition timing enough cause that much extra heat.
With the thermostat, remove it and watch it operate outside the engine.
I have also had amazing heat generation just from a tank of cheap gasoline.


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## rocco_16v (Dec 31, 2007)

*Water pump thermostat testing.*

I've never worked or own a W12 but my experience with the MK4's which were designed at about the same period as the W12 suggests me to go with the water pump. The OEM pump on the MK4's I've owned or worked on had a plastic impeller which I've seen fail in multiple ways including broken pieces, worn out blades and the impeller becoming loose (usually when hot) and not spinning at the same speed of the shaft driving it. All of these give out poor flow of water trought the system which would be the same behaviour as a half/non opening thermostat. 

One test I used to do was to remove the return hose to the reservoir and have it discharge directly on the filler hole so I could visually inspect the flow of water with the engine running. If the thermostat is not opening and your pump is working properly there should be a steady flow of water coming out from that small hose. Once the thermostat opens and the fans trigger on, the flow of warter coming out of that hose will reduce slightly. If the thermostat is not opening the flow would never dwindle. If the pump is failing the flow of water will be poor, intermitent or non existent. This test assumes there is no air in the system. 

Now if the fans turn on normaly at the expected temperature the fan temp sensor (fan switch) got hot water so the thermostat should've opened to allow that hot water across the radiator all the way down to the sensor. If the fans would turn off but the temperature kept rising that would support the theory of the thermostat not/partially opening, but I would NOT run a test like this as it will allow the engine to get hotter than normal for a prolonged time period.

The axiliary water pump (based on the operation in the MK4 Turbo/VR6 design) was used to keep the water circulating after engine shut off to cool down the engine/Turbo properly. It is not capable of cooling the engine while running, it simply does not have the flow volume required for this.

Just my 2 Cents.


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## 73blazer (Feb 19, 2020)

Wow the info here is never ending. Awesome resource and I hope to only provide people with the same later as I learn about "the VW" 

The fans both work, i'm not sure as to one speed or another. There is no noise,they run quietly as they can, they spin freely by hand and i'm really convinced the problem does have much to do with the fans, yes I recognize "don't ignore the bizarre" as it's always in the back of my head. I'm fairly convinced it's not a water pump as well, while there are two on this car an elec and engine driven, i get super hot heat constantly out in the cabin as it's rising. 
I went ahead and ordered a new t-stat, i'll change the spark plugs and valve cover gaskets while I'm under there being they seem to be somewhat problematic on these w12's and not knowing the full history, i'll put it at a point where I know the history. If the t-stat doesn't solve it, then it would almost have to be the water pump(s), but, I'm just not convinced it's that as I drove 100mi, with the heater on and windows open, and it was able to somewhat maintain, rising slightly, but turn the heater on and it maintained.That tells me there's some flow. (although that might indicate elec operating but not able to really cool it, and engine pump gone....but if the engine pump was really not working I'd really suspect it would overheat rather quickly.)
I'll change the coolant too while I'm at it, but the t-stat first, as from what I read you cannot change the coolant without removing the front bumper on this car and if I do that, the water pump isn't far behind in that procedure, so I'd change that too. Unless there's another way to tell if t-stat vs. water pump....


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## invisiblewave (Sep 22, 2008)

If the fans aren't making a noise, they're not running properly! They're pretty loud when stationary.


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## 73blazer (Feb 19, 2020)

They make air moving noise, what I meant was, no bearing noises or grinding or buzzing/havings issues starting anything of that nature.


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## invisiblewave (Sep 22, 2008)

Gotcha. There's another thread somewhere about intermittent overheating.


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## 73blazer (Feb 19, 2020)

Well I took my old theromostat out today, new ones supposed to be here Monday.

A couple issues. 
1) seems there's more oil in the intake than I would think there should be. The PCV filter where fitted to the intake had small drops of oil on them. DO I need new PCV filters on each side? Or is something else wrong in the crankcase vent system?









2) When removing the "hose" (quick coup) fitting from the front of the t-stat, that whole quick coup fitting.... pull the ring and it slides back. No problem. It slides back with my fingers. WHen I did that, the one smaller side nipple a hose was hooked up to broke off that "hose fitting" from just moving it back 1" . That plastic 90 part of the hose with a nipple for another hose seems to be extremely brittle. 
From what I see inthe parts book that's part of the actual whole upper hose??? Grrr.... The coolant needs changed anyway, so ... do you really need to remove the front bumper and set the carrier to it's "service" position to change the coolant???? 

3)Resistance on that t-stat thermocouple was 15-16ohms whcih seems to match the "new" one in the map controller t-stat replacement thread if I read his meter range right. This has been replaced before, it's already the "new" style with long feeder wire no coupler at the t-stat itself. It's the AK version. (the one I ordered is AP version) . Are you supposed to be able to apply 12v to that t-stat thermocouple and have it open (I tried, it made no noises and no attempt to open. I was able to get it to open with a heat gun and it made a nasty crackling noise as it was opening but according to my IR gun it was over 330F or so before it opened at all

4) The coil paks - it was mentioned ensure the recall things been done, I have These (well I only pulled one off for now, haven't checked them all) . Also I can see some hack mechanic was working on this as there is little hack marks on the coil pak like they didn't know how to get the VW wiring connectors off. Real nice. One of the injector connectors was chewed up too had to be very careful with that one


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## invisiblewave (Sep 22, 2008)

I'd suspect the PCV, they do fail past a certain age. Is there any sign of oil around the spark plugs?


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## 73blazer (Feb 19, 2020)

I see no oil in the wells of the two coil paks i've removed one on each side just to check the numbers on them. (that $9 coil pak puller tool was a good investment!)
I've not pulled the plugs yet as I don't have the new ones yet. Monday, so I didn't want a bunch of empty holes to fill.


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## 73blazer (Feb 19, 2020)

I ran some tests on this thermostat. 

So, first, i placed it in a giant pot of boiling salt water, according to my kitchen rod thermo and my IR gun it was 230F, it did not open. 
Next, after an hr or so, I applied 12v to the thermocoupleing (not really knowing how it's to react). Nothing

Next I heated the t-stat with a heat gun until my IR gun said 200---220-250-270 not opening...300-320....., then....it opened, with a noise, crackling, nasty bad noises. 

An hour later, the IR gun said 90F, i heated it...it opened at around 190F. Let it cool, watched it closing, applied 12v again to the thermo couple and it started opening. So that thermocouple will work but it need to be near operating temp to work is my understanding, which it was. 

Let it cool , heated with the heat gun again, opens at 200F or so. so...let it cool somewhat...it closed....IR said 170ish...applied 12v to the thermocouple, after a min or so...it start opening. remove 12v, closes. apply 12v, opens. .it appears working now, but that first open took 300F+ to get it to open. My theory is it was stuck. Or it's fine and it's something else (but what???? water flows thru the rad, its not that, fans work, it's not those, I can reach down thru the tstat opening and grab the impeller of the water pump, it's not loose on it's shaft I can't spin it. It doesn't leak. That leaves what, the two sensors? I had massively hot heat in the cabin when it was driving so I bellieve the sensors reading ok (hot) ..it was actually overheating. Had to be this t-stat.

Can't be sure yet...but it definitely needed a massive amount of heat to open on the first go around,,,,,but now seems to operate by 12v or heat gun at 190-200F or so. I even put it back in the boiling salt water and watched it open. I believe it was "stuck" . Nice.

If I was running purely on the "small" coolant circuit, that would explain why it couldn't keep temp at speed but seemed to cool a bit with lower speed or turning the heater on. We'll find out quickly here....


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## Phaetonlvr (Feb 26, 2013)

73blazer said:


> Well I took my old theromostat out today, new ones supposed to be here Monday.
> 
> A couple issues.
> 1) seems there's more oil in the intake than I would think there should be. The PCV filter where fitted to the intake had small drops of oil on them. DO I need new PCV filters on each side? Or is something else wrong in the crankcase vent system?


That's about the same amount of oily residue on the intake runners as mine has. The PCV system always has some oil in the hoses on all my W12s, seems to be normal.



73blazer said:


> 2) When removing the "hose" (quick coup) fitting from the front of the t-stat, that whole quick coup fitting.... pull the ring and it slides back. No problem. It slides back with my fingers. WHen I did that, the one smaller side nipple a hose was hooked up to broke off that "hose fitting" from just moving it back 1" . That plastic 90 part of the hose with a nipple for another hose seems to be extremely brittle.
> From what I see inthe parts book that's part of the actual whole upper hose??? Grrr.... The coolant needs changed anyway, so ... do you really need to remove the front bumper and set the carrier to it's "service" position to change the coolant????


Seems like our Phaetons are getting to the age where all the plastic fittings in the cooling system are starting to age and get brittle from too many heat cycles. I recently had a similar size nipple break off on the main heater hose, all it took was moving that little coolant line that runs in front of the Oxygen Sensor Connectors on the firewall and it broke clean off. Your hose is the upper main coolant hose and includes the large plastic connector fittings on both end and also includes the temp sensor, part # for the hose: 3D0-122-051-K. 

No need to put the front end into service position to drain the coolant, just disconnect the lower coolant hose at the radiator and you'll be able to drain most of the coolant out, or you can disconnect some of the smaller hoses that connect to the main coolant hose in that same area. You can get to that from below after removing the lower front belly pan cover.


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## 73blazer (Feb 19, 2020)

Phaetonlvr said:


> That's about the same amount of oily residue on the intake runners as mine has. The PCV system always has some oil in the hoses on all my W12s, seems to be normal.
> 
> 
> 
> ...


Yup, I was able to drain probably 80-85% or pretty close to 4 gallons of it out from the lower radiator hose and the smaller dia hose pipe on drivers side lower. The manul shows to remove some other hoses but mine doesn't really look like the pics in the manual for some reason. unless it's some funky angle they're showing. I'm not seeing any other hoses you can get at easily enough that don't connect to the two I already removed. It's easy enough to put new coolant in and change it again at the next oil change. 
I'll have to order that upper hose on monday and wait 

The one you spec'd with suffix K is the "hot country" version. There another with suffix C that says "not hot country" While it can get hot occasionally here in MI USA, I sure wouldn't consider it hot country. Or is that just a better part? I kinda wonder what the difference is.


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## mellowmutt (Apr 26, 2016)

Phaetonlvr said:


> Seems like our Phaetons are getting to the age where all the plastic fittings in the cooling system are starting to age and get brittle from too many heat cycles.


Yes indeed! I've had a year-long odyssey now with the cooling on my 12-cyl. The dual-radiator-fan unit failed, I'm working on rebuilding the old one because boy howdy are the costs adding up (hope for your sake it's a thermostat issue). $2,500 for a new unit to be shipped from Germany. Front nosecone needs to be removed to replace this, two-man job, big labor charge. Which resulted in a lot of busted plastic clips, and broken (due to being brittle, not carelessness from the shop) plastic -- I've been running on one fog lamp since November while waiting for new plastic to re-install the driver-side foglamp, had to go to the bodyshop first to get painted, finally ready two months ago but coronavirus lockdown, looking to finally have this repair completed next month...

I also live in rural America and most of my driving is mountain back roads, not gridlock, so water temps didn't get too high without the fans as long as I could get my speed up... what got scary were the oil temps. Replacing the fans made almost no difference in coolant temps, heat soak into the oil is under control now, I think the radiator fans also blow air over the oil cooler? Can't remember precisely, nor can I remember if it's the same part as my 8-cyl, I don't think so?

Anyway, the total repair bill due to fan failure is approaching 1/3 what I paid for the car! Knowing what I know now, I still don't think I could remove/replace the nosecone in-house without a whole bunch of Phaeton-specific plastic clips in stock, or breaking old and brittle plastic ancillary to the task-at-hand.

So I really hope you're having a thermostat issue, standard cheapo Bosch part I'd throw at the problem with fingers crossed, because otherwise... yikes.


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## 73blazer (Feb 19, 2020)

Well I guess compared to fans, the t-stat is cheap. But that's the most expensive t-stat I've ever bought!
We'll see. There's only so many things it can be. The car was designed to do 186 in some extreme heat for 24hrs...so somethings broke.


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## Phaetonlvr (Feb 26, 2013)

73blazer said:


> Yup, I was able to drain probably 80-85% or pretty close to 4 gallons of it out from the lower radiator hose and the smaller dia hose pipe on drivers side lower. The manul shows to remove some other hoses but mine doesn't really look like the pics in the manual for some reason. unless it's some funky angle they're showing. I'm not seeing any other hoses you can get at easily enough that don't connect to the two I already removed. It's easy enough to put new coolant in and change it again at the next oil change.
> I'll have to order that upper hose on monday and wait
> 
> The one you spec'd with suffix K is the "hot country" version. There another with suffix C that says "not hot country" While it can get hot occasionally here in MI USA, I sure wouldn't consider it hot country. Or is that just a better part? I kinda wonder what the difference is.


I believe I read somewhere on here that all NAR Phaetons were "hot country" spec. I believe part of that option is the supplemental radiator on the W12 (located on the RH side just in front of the washer reservoir) including additional coolant lines. You should verify with a VW dealer parts department which is the correct hose per the VIN, that's the only reliable way.


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## Phaetonlvr (Feb 26, 2013)

mellowmutt said:


> Yes indeed! I've had a year-long odyssey now with the cooling on my 12-cyl. The dual-radiator-fan unit failed, I'm working on rebuilding the old one because boy howdy are the costs adding up (hope for your sake it's a thermostat issue). $2,500 for a new unit to be shipped from Germany. Front nosecone needs to be removed to replace this, two-man job, big labor charge. Which resulted in a lot of busted plastic clips, and broken (due to being brittle, not carelessness from the shop) plastic -- I've been running on one fog lamp since November while waiting for new plastic to re-install the driver-side foglamp, had to go to the bodyshop first to get painted, finally ready two months ago but coronavirus lockdown, looking to finally have this repair completed next month...
> 
> Anyway, the total repair bill due to fan failure is approaching 1/3 what I paid for the car! Knowing what I know now, I still don't think I could remove/replace the nosecone in-house without a whole bunch of Phaeton-specific plastic clips in stock, or breaking old and brittle plastic ancillary to the task-at-hand.


I'm a little surprised they charged you that much. Honestly, taking the front bumper cover off (nose cone) is a 20 minute job at most if you are experienced and you only need a second person to lift it off the car so it doesn't twist and crack. Even moving the front end into the service position is pretty straight forward with the hardest part disconnecting the coolant hose (can be sticky at times). The fans are expensive new but readily available used and significantly cheaper that way and super easy to install when the front end is in the service position, literally four screws hold it to the back of the radiator support.

Some of the plastic parts on the front bumper cover are fragile, specifically the tabs on the fog light covers break off easily. In my experience the bumper guides (LH, Center, RH) that hold the front bumper in place and support the headlight washers, are always broken but again, those are less than $200 new for all three when bought online.




mellowmutt said:


> I also live in rural America and most of my driving is mountain back roads, not gridlock, so water temps didn't get too high without the fans as long as I could get my speed up... what got scary were the oil temps. Replacing the fans made almost no difference in coolant temps, heat soak into the oil is under control now, I think the radiator fans also blow air over the oil cooler? Can't remember precisely, nor can I remember if it's the same part as my 8-cyl, I don't think so?


The W12 has a heat exchanger for the engine oil so no airflow needed as it is an oil to coolant heat exchange. Of course your coolant temp should be in the normal range which will require working coolant fans.


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## 73blazer (Feb 19, 2020)

Phaetonlvr said:


> I believe I read somewhere on here that all NAR Phaetons were "hot country" spec. I believe part of that option is the supplemental radiator on the W12 (located on the RH side just in front of the washer reservoir) including additional coolant lines. You should verify with a VW dealer parts department which is the correct hose per the VIN, that's the only reliable way.


Ah well then it could be the K has more nipples on that t-stat fitting than the C version and not just some material difference. Yeah, i'll have to check with a stealer then. 

FYI< I was able to get a bit more coolant out by standing my daughter up on the lift and having her pour in new coolant in the coolant bottle and in the t-stat opening on the top of the block until I saw it run clear out the bottom, probably another 1/4+ gallon,then took the air gun and blew in hoses on the top fitting that connects to the tstat... that spit some a little more dirty coolant out . I think I got the vast majority of the old coolant out. Jebus, this car is no small block chevy, can't just dump the lower radiator hose and have a cigar. When I first dumped the lower rad hose I believe that only drained the radiator for the most part, in fact when I looked at the t-stat opening the block was still mostly full of coolant, only about 1.5gallons came out of that lower rad hose. The vast majority came out of the smaller dia hose that connects a hard pipe the follows under the radiator and connects to a hose on the drivers side, from both sides of that disconnect. Just the way the lines are run, I'm sure there's plenty of low spots in those lines too. I'd flush it but the dealer doesn't sell the full concentrate and if you flush it with water and only put 50/50 they sell back in then it's gonna be less than 50/50 which is not ideal for MI. I got a good 4 1/4 gallons I'm pretty sure.


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## 73blazer (Feb 19, 2020)

OMG are you kidding me, the PCV breathers are $150 EACH???? Is there some magic in these or like all the rest of vehicles for decades where it's really nothing more than a piece of filter material with a check valve in a plastic housing?????


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## PowerDubs (Jul 22, 2001)

Well the engine is $30,000 so $150 for a part doesn’t seem too bad. 

I cracked a stupid breather hose trying to get the airbox open- whoops, it’s $200- yea, for a dumb basic plastic hose that is maybe 8 inches long.

Come to think of it, the 30k for the engine doesn’t come with all the stuff attached either.

Just hope your starter never fails.


Sent from my iPhone using Tapatalk


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

73blazer said:


> OMG are you kidding me, the PCV breathers are $150 EACH???? Is there some magic in these or like all the rest of vehicles for decades where it's really nothing more than a piece of filter material with a check valve in a plastic housing?????


There are many VW dealers and others that sell Genuine VW parts on the Internet. 

In alphabetical order:

eBay of course. Also good for used parts. I put my search for world wide. Most of the best used parts come from Germany where the parts are usually clean and a $2,000.00 harness wasn't cut to remove a $10.00 switch. (Exaggerated for effect.)

https://www.ecstuning.com/

https://www.fcpeuro.com/

https://www.getvwparts.com/

https://www.jimellisvwparts.com/

Might as well check Rock Auto also:

https://www.rockauto.com/ 

https://www.vwpartscenter.net/

https://www.vwsb.com/parts-center-index.htm

https://www.vwpartsvortex.com/

These guys make some billet parts for Phaetons, especially the 4.2 V8:

https://www.gruvenparts.com/


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## 73blazer (Feb 19, 2020)

53PL-50AAA-VW611BAN said:


> There are many VW dealers and others that sell Genuine VW parts on the Internet.
> 
> In alphabetical order:
> 
> ...


Thanks for the list. Yeah I've already ordered plenty from jimellis and vwpartsvortex and ecstuning. Rock also seems to list genuine vw parts for alot of stuff they must have a standing deal with a dealer nearby them. 

The PCV breather I took one of mine apart (they come apart pretty easy) There's no filter like most PCV breathers I'm used to, just a movable rubber gasket with a spring. So this one is just a check valve. The rubber on the gasket is worn into it's seating cone and probably allows too much bypass is my guess. I'll probably just get news ones, but these may be able to be "reman'd" . The cone doesn't seat perfectly in the middle of the gasket so if you removed the gasket and rotate it, the cone would seat in a completely different place on it. For the spring, I'd need a new one to get the spec for the spring force though, it may be worn as well. 

The hose.....WTH, the 3D0122051K is the one I need(apparently all NA is "hot country"), however, VW says no longer produced and unavailable. Real nice. A radiator hose. 
Sooo...while I'm quite versed in sourcing GM NOS parts, VW NOS parts I've no idea where to look. Kinda don't want a used one of these.


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## Phaetonlvr (Feb 26, 2013)

73blazer said:


> Thanks for the list. Yeah I've already ordered plenty from jimellis and vwpartsvortex and ecstuning. Rock also seems to list genuine vw parts for alot of stuff they must have a standing deal with a dealer nearby them.


Excellent parts supplier list. Personally I order most from 1stvwparts which is a dealer up in WA state because I'm on the West Coast and shipping is pretty fast from them. I've built up a personal relation ship with them and I usually just email them a list of parts I need and they check everything against the VIN to ensure there are no parts that are superseded. If I don't know a part number I just sent them a diagram and they'll look it up and send me ETKA screenshots to verify. They will also tell me which distribution center has it in stock to see how long it takes to get it and they can also check stock in Germany. Until last year they could "red order" (expedited shipping, usually in a couple of days) parts from Germany at no extra cost but VW changed that now and it costs extra. 

Also use fcpeuro and RockAuto all the time. I also recently found RM European out of the Denver Area, they are really nice and their prices on ZF parts (transmission) in particular are excellent and they have most of it in stock.



73blazer said:


> The hose.....WTH, the 3D0122051K is the one I need(apparently all NA is "hot country"), however, VW says no longer produced and unavailable. Real nice. A radiator hose.
> Sooo...while I'm quite versed in sourcing GM NOS parts, VW NOS parts I've no idea where to look. Kinda don't want a used one of these.


That's bad news but unfortunately not surprising that they are starting to discontinue parts for the W12s. Did you have the dealer check if there is stock in Germany? I don't know of any NOS sources either, I do see some pop up on Ebay once in a while but that's just rare and I assume it's just leftover parts from dealerships. 

Just found out that the rubber mounts for the W12 oil cooler/heat exchanger are NLA and no stock anywhere but those are somewhat easy to replicate.


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## 73blazer (Feb 19, 2020)

Phaetonlvr said:


> Excellent parts supplier list. Personally I order most from 1stvwparts which is a dealer up in WA state because I'm on the West Coast and shipping is pretty fast from them. I've built up a personal relation ship with them and I usually just email them a list of parts I need and they check everything against the VIN to ensure there are no parts that are superseded. If I don't know a part number I just sent them a diagram and they'll look it up and send me ETKA screenshots to verify. They will also tell me which distribution center has it in stock to see how long it takes to get it and they can also check stock in Germany. Until last year they could "red order" (expedited shipping, usually in a couple of days) parts from Germany at no extra cost but VW changed that now and it costs extra.
> 
> Also use fcpeuro and RockAuto all the time. I also recently found RM European out of the Denver Area, they are really nice and their prices on ZF parts (transmission) in particular are excellent and they have most of it in stock.
> 
> ...


They're checking, they'll have to get back to me. 

I did discover one thing, the Bentley W12 from 2005, the radiator comes with 3 different upper hoses "for fitment for various worldwide markets" . There's a picture of the actual part not a cartoon drawing, one of the three hoses looks like mine. Of course they want $950 for that part# which is the rad and three hoses.


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## Phaetonlvr (Feb 26, 2013)

73blazer said:


> I did discover one thing, the Bentley W12 from 2005, the radiator comes with 3 different upper hoses "for fitment for various worldwide markets" . There's a picture of the actual part not a cartoon drawing, one of the three hoses looks like mine. Of course they want $950 for that part# which is the rad and three hoses.


Interesting and maybe it would fit but the length of the actual rubber hose is pretty short so not much flex in case it is even an inch longer or shorter and not an exact same part. Maybe search for the Bentley hose on German Ebay to see if you get better/more detailed photos to compare it.


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## 73blazer (Feb 19, 2020)

Well. They're saying no available anywhere Europe middle east na nowhere. So. I guess used if I can find a used one which I can't seem to at the moment......or I could reengineer that inlet ...i dont think a repair on the nipple.would hold up but a plug/seal would.... plug my hole in That 90 fitting and plumb that other small hose into another hose that's connecting to that same tstat outlet? . . The Audi w12 sells a straight quick.coup piece that connects to the same tstat no hose piece with it just a little plastic quik coup piece. . It's not 90. But you can connect whatever hose you want there. Not sure that helps me though still.would need all new rengineering in that plumbing in that area. Grrrrr...well this sucks. Have to figure something out for this though.


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## 73blazer (Feb 19, 2020)

This car.is starting to remind me of an episode of the twilight zone.when the dealer came back with the words "that part is listed internationally as obsolete". You mean you don't make it anymore. That's fine. But it's not obsolete. The tz episode was "the obsolete man" . "Your a bug...an anachronism like a ghost from another time" . I think there may be some threaded fittings I can jamb in there from inside with a gasket and thread a nut on the outside to secure it to that plastic housing. Just one idea. Ill.come.up with something. Never thought a radiator hose would be obsolete. 😯


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## 73blazer (Feb 19, 2020)

Yeaaahh...here's what I got...










Sadly 3d0122291c (the fitting itself) doesn't seem to exist. So...need to find a way to fix this that will hold up.


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## Phaetonlvr (Feb 26, 2013)

That's a bummer! I did look up the suffix C version and it seems the only difference is that on the t-stat inlet it's missing the larger nipple (the one that is still good on yours). 

Taking a quick look at the cooling system diagram it seems that this larger hose goes to the supplemental radiator. The smaller hose goes straight to the coolant reservoir. I guess you could get the suffix C version and then bypass the supplemental radiator but that would be somewhat drastic. I'd probably just try to plug the small hole where the nipple broke off. I'm not entirely sure what that little hose is needed, maybe to relief any air in the system straight to the reservoir?

https://volkswagen.7zap.com/en/usa/phaeton/phae/2004-258/1/121-121060/#38


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## PowerDubs (Jul 22, 2001)

Threaded brass nipple?


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## 73blazer (Feb 19, 2020)

Phaetonlvr said:


> That's a bummer! I did look up the suffix C version and it seems the only difference is that on the t-stat inlet it's missing the larger nipple (the one that is still good on yours).
> 
> Taking a quick look at the cooling system diagram it seems that this larger hose goes to the supplemental radiator. The smaller hose goes straight to the coolant reservoir. I guess you could get the suffix C version and then bypass the supplemental radiator but that would be somewhat drastic. I'd probably just try to plug the small hole where the nipple broke off. I'm not entirely sure what that little hose is needed, maybe to relief any air in the system straight to the reservoir?
> 
> https://volkswagen.7zap.com/en/usa/phaeton/phae/2004-258/1/121-121060/#38



Yeah bummer indeed



53PL-50AAA-VW611BAN said:


> Did you check the dealer?
> 
> Every hose I looked up looked similar but no cigar. Maybe VW changed it.
> 
> ...


I checked with 2 dealers directly, both said so sale, not available anywhere in the world, discontinued. "obsolete" actually was their word. The C one is available but for cars without aux radiator or (not hot country), as phaetonlvr pointed out, that's missing the largert nipple off the fitting. . I don't know what the AC one is not seen it. I could perhaps look up for 2004 or 2006 I hadn't thought of that as I wouldn't think they'd be different..but I'll have a look. I tried Bentley, the only number I could up with there for the hose it was part of a whole radiator with three hoses "for different worldwide markets" one hose looked like mine. But that was $950. I couldn't seem to find a hose by itself bentley number. I can look again The number on my hose is the K number or the number for the whole hose assembly, there are numbers on each fitting itself but yeah...I don't believe they ever sold those as actual service parts. 



PowerDubs said:


> Threaded brass nipple?


Yup, there is enough meat there on that embossment and the inside is actually flat in that area too.The embossment is ~5mils thick. I'm not sure I'd want to thread into the plastic directly. I was thinking of this, this is the only one I can find small enough (that you don't have to buy a 1000 of that is) Drill it out, pop this in, put a barb nipple on the threads done...I wish it was brass or alum, but all the brass and alum ones I find are for 1/2" hole or bigger.


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## 73blazer (Feb 19, 2020)

Well my local hardware store didn't have much in the small dia. stuff. So I ordered a myriad of thru wall bulkhead fittings and a few extra threaded nipples as well, there's a 6mil thickness and 12mil dia on that boss so there should be enough meat there to thread a 4.8mm nipple in it. If not, I can drill it a bit bigger and try a thru-wall sealed barb fitting. Unless somebody wants to sell me a used hose assembly 
I found the Bentley hose #'s, while they have the small nipple on that main fitting that's broke on mine, they don't have the bigger one that leads to the aux rad. I guess none of the bentleys included the aux radiator. Barring anything else working though, I'm sure I could use one of these bentley hoses and just plumb the extra phaeton fittings into the return hose itself in some manner with some extra fittings or plug my hole and plumn that small line in somewhere else. Just what this car needs, more plumbing in that area. I'm sure something will work here, just like to find a way to test whatever I come up with before it's installed as removal isn't exactly easy if I find somethings not working. Well it's not hard, I'd just rather not keep taking it apart to find a working solution.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

73blazer said:


> I checked with 2 dealers directly, both said so sale, not available anywhere in the world, discontinued. "obsolete" actually was their word. The C one is available but for cars without aux radiator or (not hot country), as phaetonlvr pointed out, that's missing the largert nipple off the fitting. . I don't know what the AC one is not seen it. I could perhaps look up for 2004 or 2006 I hadn't thought of that as I wouldn't think they'd be different..but I'll have a look. I tried Bentley, the only number I could up with there for the hose it was part of a whole radiator with three hoses "for different worldwide markets" one hose looked like mine. But that was $950. I couldn't seem to find a hose by itself bentley number. I can look again The number on my hose is the K number or the number for the whole hose assembly, there are numbers on each fitting itself but yeah...I don't believe they ever sold those as actual service parts.



The AC is the whole hose also. I somehow missed where you said earlier that 3D0122051K was your hose. 

ECS says it ships on Jul 16. Don't hold your breath:

https://www.ecstuning.com/Search/SiteSearch/3D0122051K/

It was VW San Bernadino that said the AC is the one for my Phaeton:

https://www.vwsb.com/parts-center-index.htm?path=/search?search_str=3D0122051K

But when I put 2005 as the year, 3D0122051K is correct but discontinued:

https://www.vwsb.com/parts-center-i...s/volkswagen-radiator-coolant-hose-3d0122051k

The official VW parts website does say it's discontinued:

https://parts.vw.com/p/48259463/3D0122051K.html

The seller from Latvia on eBay shows he has one. I have bought from him before. I think he bought a bunch of Phaeton parts. His prices are usually way more than U.S. dealer prices but I found something I needed, he had it and that part was reasonably priced. It was a part I was looking for since late 2014 and was in y eBay searches.

https://www.ebay.com/itm/NEW-Genuin...616819?hash=item3b3b385073:g:DwIAAOSwndFdrrgd

The drawing for 3D0122051K doesn't look at all like it has the connector you showed so I was dismissing those out of hand. 

The Bentley site I went to has drawings like the VW drawings. Which Bentley site did you go to that has accurate pictures?

Here is the site I check:

https://www.scuderiacarparts.com/carparts/marque/bentley/bentley-parts.html


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## 73blazer (Feb 19, 2020)

53PL-50AAA-VW611BAN said:


> The AC is the whole hose also. I somehow missed where you said earlier that 3D0122051K was your hose.
> 
> ECS says it ships on Jul 16. Don't hold your breath:
> 
> ...



Well, from what I could tell the AC hose is for the 4.2l V8.
ecs just has a deal with a dealer down from the road from them. SO they'll quickly find the K hose is discontinued. 
The Latvia guy I did notice that, i didn't contact him, the price seemed a bit out of hand with shipping is silly, and I just assumed he was some dealer proxy like alot of sellers, no actual stock....... But...if you say he's actually got parts...that could be interesting. 
Bentley I found this one: 
https://www.flyingspares.com/shop/b...-to-2006-models/radiator-hoses-3w0198115.html 
but on closer inspetion none of those hoses look like mine, at least not the fitting part. And I've come to find the Bentleys did not have the aux radiator like the w12 Phaeton so they're all missing the big num off my fitting
And the scuderia place you mention has listed the actual hoses. THe P# for anything w12 bentley I can find is 3W0 121 051 H which you can find actual pictures of, very close, looks like same hose it has the small nub that's broke on mine, but without the big nub that leads to the aux radiator .
For fun I also tried taking my part # 3d0122051K and trying 3w0122051k...sadly doesn't exist. 


I'll try fixing this. If it doesn't work, mabey the latvia guy....I dunno


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

73blazer said:


> Well, from what I could tell the AC hose is for the 4.2l V8.
> ecs just has a deal with a dealer down from the road from them. SO they'll quickly find the K hose is discontinued.
> The Latvia guy I did notice that, i didn't contact him, the price seemed a bit out of hand with shipping is silly, and I just assumed he was some dealer proxy like alot of sellers, no actual stock....... But...if you say he's actually got parts...that could be interesting.
> Bentley I found this one:
> ...


Man,

The VW San Bernradino website "knows" my Phaetons so it came up to 2004 right away. I didn't notice it "forgot" I own W12s. 

I don't know that the Latvian guy has the parts in hand, but he does list parts that others have said were NLA and I did get a part that was NLA as far as I know. 

The Latvian seller is usually more than dealer prices, sometimes way more. If he's the only new source, he has a monopoly. 

If you think the hose is expansive, you should see what he wants for Phaeton wood steering wheels. 

You could contact him to make sure he actually has it.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

I put 3w0122051 in an eBay search and there were a bunch of new 3w0122051C hoses. 

It's two hoses with a center part that has a large outlet. Does your original hose also have a center part with a large outlet?

If not do you think the aux radiator hose will reach the center?

Thanks for the Fling Spares website. I suspect Bentley Continental parts will be plentiful longer.


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## 73blazer (Feb 19, 2020)

On inspection of those thru wall fittings they are much larger than the "sales spec" seems to indicate. the one saying "for hole size 4.8mm" is actually over 1/2" in dia. Not sure what the 4.8mm part is. But, it's the smallest one and way too big. Plus after thinking about it if that inside nut happens to come off, it's going straight for the t-stat, and if it doesn't jamb that up, it's going into the engine block, I don't much like that idea. 

I think the 1/16" NPT to 1/4" hose barb will fit that boss nicely. I ordered it in brass (which actually says only good to 150F??? not sure why the brass has a low temp rating) and acetal plastic which says A rating for glycerin (G13 coolant) or glycol and it's temp rating is -40f to 350F. I actually think the hose fitting itself from VW might be acetal plastic. The hose barb that broke off is actually slightly larger than 1/4" or about 7.5mm (0.29") but trying to find mm sized anything in the US in small dia fittings like this ....that you don't have to buy 1000's of to get them is tough. 1/4" will work just fine. 

That boss on that hose 90 fitting for this barb is 14mm dia and 6mm thick. 1/16" npt is 0.3125" max dia (or about 8mm)..... an 8mm dia. item in that 14mm boss leaves 3mm of meat around the whole edge. 1/4" npt is too big. I ordered a 1/16 NPT tap and required goofy size .242" required drill bit to go with it. Before this I didn't even know there was a 1/16" NPT, I knew 1/8" and have a 1/8npt tap. but never heard of 1/16" npt. 

We shall see, I feel pretty good about it's chances. We'll see how it taps.


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## PowerDubs (Jul 22, 2001)

I wouldn't trust just treading it in...I'd get some sort of a suitable high temp epoxy paste just to be safe.


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## 73blazer (Feb 19, 2020)

Oh don't worry. I've plenty of Henkel (loctite) oem training kits with 10s of different loctite substances some for shaft key glue some for threadlockers. Some for just glues some for sealants some for sudo plastic welding . Most of them are not found in stores and are designed for various oem applications. Just need to pick the right one.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

Did you look at the new 3w0122051C hoses on eBay to see if they would work?

Search for 5Q0122291BL on eBay. It might work.


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## 73blazer (Feb 19, 2020)

The 3w0122051C hose , at least the coupler that goes to the t-stat piece part of it, is missing the big nipple to the aux radiator (very much like 3d0122051C for phaeton "not hot country" or sans aux radiator)

That other piece 5Q0122291BL is very interesting. It has both the large and small nipple needed. However, upon closer inspection both of them are going the wrong way. The big nipple is pointed down and even back some and the little nipple is pointed straight up. In the area there, there are other hoses the pcv connector between the two valve covers and some other hoses. There might be something to do with the little one, but the big one I don't think you could plumb your way out of that one, there's no room to be pointing down and add fittings in the area where that would point. That's a bummer because when it first came up it looks pretty darn close.


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## PowerDubs (Jul 22, 2001)

73blazer said:


> Oh don't worry. I've plenty of Henkel (loctite) oem training kits with 10s of different loctite substances some for shaft key glue some for threadlockers. Some for just glues some for sealants some for sudo plastic welding . Most of them are not found in stores and are designed for various oem applications. Just need to pick the right one.





Geez....and my friends think I am a geek for having green loc-tite.

For most people glue is glue, tape is tape, oil is oil....and WD40 is (wrongly) used for everything...


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

The 3w0122051C hose has that T-fitting in the middle.

In post #73, I asked if the original hose had a T-Fitting in the middle.

If the 3D0122051K doesn't have a T-Fitting, could the T-fitting on the 3w0122051C be used for the auxiliary radiator hose?


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## 73blazer (Feb 19, 2020)

53PL-50AAA-VW611BAN said:


> The 3w0122051C hose has that T-fitting in the middle.
> 
> In post #73, I asked if the original hose had a T-Fitting in the middle.
> 
> If the 3D0122051K doesn't have a T-Fitting, could the T-fitting on the 3w0122051C be used for the auxiliary radiator hose?


Right, you did. Sorry. The answer is, yes my K hose has the t in the middle. I think that goes down to the aux elec. pump. The real issue, that damn motor is so jambed in there, there really isn't much room to be replumbing a whole lot. Nothing can be pointing lower in the center for sure as the water pump is right there with the moving belt. Any replacement is gonna need to be fairly close, or, big trail and error and plumbing job to connect what you want. 

I did get my new fitting and tap and bit today. That looks like it's going to work .
But there's an additional problem. The hole for the nub that broke off, is not centered in the boss. (nice!). So if I try to drill it'll want to wander into that existing hole to make that bigger for my tap then be too close to an edge. 
Fortunately my buddy has a bridgeport with a 3/16" end mill bit which won't wander. So I'll have to bring it over his house to get my new slightly bigger hole perfectly centered in the boss, then final it with the .242 bit, then tap it.


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## Phaetonlvr (Feb 26, 2013)

53PL-50AAA-VW611BAN said:


> The 3w0122051C hose has that T-fitting in the middle.
> 
> In post #73, I asked if the original hose had a T-Fitting in the middle.
> 
> If the 3D0122051K doesn't have a T-Fitting, could the T-fitting on the 3w0122051C be used for the auxiliary radiator hose?


The original 3D0122051K does not have a T-Fitting in the middle like the Bentley version but rather has a long sweep 90 radiator outlet fitting and at the end of that fitting is the t-fitting. It only has one hose section unlike the Bentley. I guess you could try to install an additional t-fitting in that area but, as has been said before, the area is so tightly packaged that it would be very difficult to do IMHO.


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## 73blazer (Feb 19, 2020)

This seems like a good fix. centered the hole with my buddies endmill bit in a bridge port, finaled the hole with the .242 bit and tapped with the 1/16 NPT tap. 
Plenty of meat all around and lots of thread engagement. With the right sealant this should be just fine. 
I did have to remove the perma clamp in order to hold the piece in the bridgeport properly. But I have stainless clamps around so I'm hoping there's enough room for a screw which the perma clamp didn't have. 



























I'm out of town until middle of next week i think I can finally start re-assembly of my car.


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## Phaetonlvr (Feb 26, 2013)

Looking great, can't wait to see if it holds.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

73blazer said:


> This seems like a good fix. centered the hole with my buddies endmill bit in a bridge port, finaled the hole with the .242 bit and tapped with the 1/16 NPT tap.
> Plenty of meat all around and lots of thread engagement. With the right sealant this should be just fine.
> I did have to remove the perma clamp in order to hold the piece in the bridgeport properly. But I have stainless clamps around so I'm hoping there's enough room for a screw which the perma clamp didn't have.


The fix looks good. 

Did you save the clamp? 

It should have the size on it. They are easy to find and easy to clamp down with the right tool which is not very expensive. I think the brand is Oetiker or something similar. 

The downside is you need the correct size. The advantage is the correct clamp tightens down to the correct diameter. With the correct size permanent clamp, you can't overtighten it and cut into the hose.

You could also buy screw type "fuel hose clamps" which have a sleeve that protects the hose. You still have to tighten them "just right" like Goldilocks. Too loose, it leaks. Too tight, it deforms the hose which leaks down the line.


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## PowerDubs (Jul 22, 2001)

Yea.... that should work fine. :thumbup:


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## mellowmutt (Apr 26, 2016)

73blazer said:


> I ordered it in brass (which actually says only good to 150F??? not sure why the brass has a low temp rating)


Nickel-plated brass has certain advantages over regular brass, the two important ones for cooling systems are lower thermal expansion, and higher corrosion resistance. The lower coefficient of friction is important for other applications, like ammo jackets. I've machined lots of brass on lathes and bridgeports, gotta keep the part cooled.


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## johnnyjiang (Feb 24, 2014)

overheating is actually quite common. I had 2 phaetons and they all overheat. one at 90k miles and one at less then 25k miles.

problem is the coolant sensor at the lower front. The reading u get in VCDS should be the same as the gauge, which is measured by the upper rear sensor.

Thats most likely the cause. if not check your fans.


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## 73blazer (Feb 19, 2020)

Jebus. I got the t-stat and hoses re-installed. One has to approach this car with patience. Working on those myriad of hoses in the front of that engine block is a royal pita. I replaced a two clamps with torque constant screw clamps that are FAR easier to use and re-use and remove and install than crimp hose clamps. I have the "hose clamp tool" but you cant get it near any of those hoses. The factory must have had special super bent up versions of hose clamp tool because I have a few sizes of them and none them can get in that area. While screw clamps are less in total diameter force, they seemed to have worked for decades on other cars of mine, and I have stainless clamps with stainless screws so I'm quite confident in them. 
Whew, there is just no room up in front there to work, even with the lower and upper intake removed. I'm replacing the two temp sensors while I'm at it since, well, they seem to be a common trouble and the one in the rad hose area was caked with some white dust. Just trying to get the hoses back on the nubs is rough. YOu can get behind some of those hoses to push them back on. But, once all installed, it's all tight and nothing is gonna move or vibrate much, all contained within every few inches, so I'm hoping my fix will be good. 
Hoses all re-installed. Just waiting on my new PCV breathers and a temp sensor o-ring (the VW official version sensor doesn't come with new oring and one fell out dropped down and...well I can't find it). Installed new spark plugs and hoping for the best!


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## Phaetonlvr (Feb 26, 2013)

Well said! It's not so much the W12 itself but rather the super tight packaging of that engine in the Phaeton engine bay that makes it so challenging to work on. On the V8 you can get both arms in-between the engine and the radiator but on the W12 you can't even get one hand down there.

Earlier this year I broke off a similar sized coolant nipple on the main heater hose (at the firewall, in front of the brake master cylinder) and had to remove and re-plug the heater hose right below the master cylinder, super tight and I nearly gave up but managed in the end.


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## 73blazer (Feb 19, 2020)

Mother puss buckets. 

While I havn't put the upper or lower intake back on yet, I got the new sensors both in and hoses all hooked back up. 
I go to pressure test it again, and there's a leak.A very small one, but the needle looses a psi every 45s-1min. Where....the body of that hose to t-stat plastic fitting. The one I drilled and tapped. I knew something was wrong with that fitting, the hose to rad plastic piece is clean black plastic mabey slightly discolored from age and use. The t-stat to hose fitting end was all brown inside and the plastic was soft-ish, you could gouge it with your finger nail. Definitely not the same supplier as the plastic fitting on the other end of the hose. Buy hey, my drill and tap is not leaking  . It's probably why that nipple broke off to begin with, defective plastic. 
So it has a taperdown on it and it's leaking there. not where I drilled, not the oring, but the actual body of the fitting. 
Jebus. 
AND, there's another albeit very very small leak, the center plate cover behind the t-stat, that's leaking. I didn't even touch that!! WTF. From the looks of the block near it, you can see it appears it's been leaking, probably seals when it's hot but spits a bit when it's cold. I didn't even notice that, my soapy water bottle happen to drip just after spraying the front hose fitting and holding it my hand while I was watching the hose fitting and bubbles, it drips onto the edge of that center plate and starts bubbling..... i'm like...WTH is going on here. that's leaking too???? :banghead:
I tested this before , while the intakes were all on, it held for several minutes. 

In the picture here you can see my new fitting I drilled and tapped, that's not leaking. It's literally leaking at the taper down joint, that whole fitting is wrecked. 









I guess I'll try the ECS tuning. While I had called 3 dealers myself and visited another in person all of which said that hose was no where to be found even in Europe or the middle east or China, they also said the same about those breathers, and ECS managed to come up with the breathers. Mabey they can come up with the hose???
The next option would be the Latvia eBay guy. The next option would be to try and measure and 3D print one. The next option would be to epoxy the crap out of the outside of that fitting.


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## Phaetonlvr (Feb 26, 2013)

Sorry to hear about that. What a bummer. Hope you can find a replacement and please keep us posted, it's going to be a problem for all of us W12 owners sooner or later.


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## 73blazer (Feb 19, 2020)

Yeah, my pic from post 64 when I first got this out:









The circle I was showing where the nipple broke off. But look just to the left of my yellow circule. 

YOu can see that taper joint and brown discoloring on the top there, right where it's leaking. It appears, it may have been leaking every so slightly there to begin with!


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

73blazer said:


> Mother puss buckets.
> 
> I guess I'll try the ECS tuning. While I had called 3 dealers myself and visited another in person all of which said that hose was no where to be found even in Europe or the middle east or China, they also said the same about those breathers, and ECS managed to come up with the breathers. Mabey they can come up with the hose???
> The next option would be the Latvia eBay guy. The next option would be to try and measure and 3D print one. The next option would be to epoxy the crap out of the outside of that fitting.


Sorry to hear that. Message that Latvian seller on eBay to make sure he or she has it. The auction says "You have to note that it can take 2-14 working days until we receive your purcashed part in our stock. After that we immediatelly will ship out your item. "

Maybe J.B. Weld it? 

I have never used it myself but it's supposed to be some miracle epoxy. 

Good luck.


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## PowerDubs (Jul 22, 2001)

53PL-50AAA-VW611BAN said:


> Maybe J.B. Weld it?
> 
> .





I came here to suggest an epoxy... I would just be very specific about which one I chose. Lots of time would be spent looking at the data sheets and chemical properties.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

PowerDubs said:


> I came here to suggest an epoxy... I would just be very specific about which one I chose. Lots of time would be spent looking at the data sheets and chemical properties.


I think J.B. Weld has the suggested uses on the package and the tube. 

I believe they have a product for coolant system use. 

Most epoxies also say on the package what materials they (supposedly) work on. 

I have looked at J.B. Weld in stores but I don't remember using their products yet. 

I know some people swear by them. I don't remember where I heard about them but knew of their products before I saw them in a store. 

I just filed them away in the back in my mind for future reference. I do need to repair a block so I might try one of their cast iron epoxies. 


A better solution would be to machine a replacement out of aluminum (or make a stainless version) with the little nipple being a separate threaded piece with a plug for the hole. You could still use it if your W12 doesn't have the other coolant hose.

That might be expensive but I think everybody with a W12 would want at least one for the future.


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## 73blazer (Feb 19, 2020)

ECS is maintaining they'll have it. From where????  Who knows. I called them to ask so I don't waste time waiting just to hear oh, uh yeah we couldn't get that. But ... they're saying they should get it.


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## 73blazer (Feb 19, 2020)

Bahahaha....they just notified me they actually can't get it. Well, I guess it's not funny, for me. 

Well, onto the Latvia guy. 

I could epoxy it, but I'm afraid there's not enough good plastic left to adhere to. Like I said, epoxy is like welding to rusty metal, you have to get down to bare metal somewhere to weld to. And most of this fitting is so soft, you can cut it with a pair of regular house scissors.


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## 73blazer (Feb 19, 2020)

Lativa guy is a no go. In fact his words almost admonish me for asking. Hey dude, your the one advertising it on ebay as if you have it!
There's a different seller, from lativa, that showed just up. and that listing says "1 sold in the last 24hrs". That's...comical. 

So, I guess it's scan and print..or machine. I'm thinking I might have it made from alum and not plastic as finding the right resin to stand up to heat, cold, cycles etc might prove to be difficult.


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## 73blazer (Feb 19, 2020)

$150 for a CT scan. I'm a CATIA guy so I get the scan data back and have to build it up in CATIA. Then I can send that model to a 3d printer or a machine shop, probably on the order of $700 for 10 parts but I need to give them a model first to get me an accurate quote. 

It's either this or use the non-hot version and rig up some plumbing somehow to make up for the aux rad nipple not found on the "not hot country" version. The real probably with that route is, there' just no room up there for additional plumbing. Right below it is the belt whirring by, above it is emissions lines, in front is fan controllers, in back is the block, there's just no room. 

If I can sell a few, that would lower my cost. I really think it's just this end of the hose assembly, as I said the middle check/valve tee thing and the other end 90 fitting with the sensor in it, that plastic seems in much better condition. This piece is, soft, where it's leaking a whole chunk of plastic has flaked off the top, i could probably push my finger nail through it. I think whoever supplied this part used defective plastic or something. There's a plastic inlet coolant fitting on my 1989 Pontiac STE and it's in perfect condition, so it's not really age alone, somethings up with the plastic in this particular piece and if that's the case, it's likely not just mine. Might not be all of them, but certainly a run around my serial number. Mines a 2005 serial 2326


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## Phaetonlvr (Feb 26, 2013)

I do have a W12 parts car with a good upper radiator hose but considering my fleet of W12s I might buy one fitting from you if you end up getting it machined or 3D printed.


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## 73blazer (Feb 19, 2020)

Well the 2nd Latvia ebay guy, claims he actually has it. 2 of them. Seems awful suspicious multiple sellers in Latvia selling this part..and the 1st one says can't get it and the 2nd listing shows up immediately after I inquired to that first guy. .but he's got a long history and high raiting...so. I ordered one from him on my AMEX so I can take back the payment if it's not what he claims it is or I don't get it. . We'll see if I get it. But I already ordered the scan of the fitting I have, so, I'll have that route going at the same time. Car's been down long enough. My buddy actually has a very good quality 3d printer and can print in the hi-temp resin ($200/L and requires and hr of UV soak and 3 hrs of oven baking after the print) . But he can print it in his cheapy resin for me so we can check the fit and quality.

I also did some research prompted by 53PL-50AAA-VW611BAN and found the reason this hose is hard to find....
It was only used on 2002-2005 BAP W12's for "hot country". When they did their W12 upgrade in 2006 to the BRP motor they totally re-did the aux rad plumbing for the hot country vehicles and upper hose on BRP 'hot country' is the same C hose used on BAP "not hot country" (aka.....less the big 5/8" nipple off that fitting that leads to the aux rad) . Only NA, middle east north Africa where "hot country" vehicles. So basically this K hose with the 2 fittings off it on the t-stat end is only good for 2002-2005 hot country w12's.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

I was wrong, the first Latvia guy is not a seller I bought from before. 

That first auction now says "This listing was ended by the seller because the item is no longer available."


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## Phaetonlvr (Feb 26, 2013)

73blazer said:


> I also did some research prompted by 53PL-50AAA-VW611BAN and found the reason this hose is hard to find....
> It was only used on 2002-2005 BAP W12's for "hot country". When they did their W12 upgrade in 2006 to the BRP motor they totally re-did the aux rad plumbing for the hot country vehicles and upper hose on BRP 'hot country' is the same C hose used on BAP "not hot country" (aka.....less the big 5/8" nipple off that fitting that leads to the aux rad) . Only NA, middle east north Africa where "hot country" vehicles. So basically this K hose with the 2 fittings off it on the t-stat end is only good for 2002-2005 hot country w12's.


That's good to know. Any way to reroute the aux radiator plumbing in our W12s to the later version? Where's the line to the aux radiator coming from on the later version?


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## 73blazer (Feb 19, 2020)

Phaetonlvr said:


> That's good to know. Any way to reroute the aux radiator plumbing in our W12s to the later version? Where's the line to the aux radiator coming from on the later version?


Of course there is! If you want to spend $1500 on hard and soft hoses and fittings, and remove the engine and transmission to install them. 
It's not just some slight change, when I look at the diagrams they are completely different for the AUX rad and AUX elec. pump , that whole mess of crap on the lower right front of the BAP cars is cleaned up and only one hose runs through there. I think another runs up and over in the tunnel area and some others in a hard lines snaked underneath somehow.


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## Phaetonlvr (Feb 26, 2013)

73blazer said:


> Of course there is! If you want to spend $1500 on hard and soft hoses and fittings, and remove the engine and transmission to install them.
> It's not just some slight change, when I look at the diagrams they are completely different for the AUX rad and AUX elec. pump , that whole mess of crap on the lower right front of the BAP cars is cleaned up and only one hose runs through there. I think another runs up and over in the tunnel area and some others in a hard lines snaked underneath somehow.


If that is all it takes  I remember now that the later BRP cars got a different engine oil heat exchanger setup on the RH side so probably that cleaned up a lot of stuff there. The only way to achieve that would be if you have a BRP parts car.


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## PowerDubs (Jul 22, 2001)

My entire '06 is a parts car.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

The Rock Auto August Early Edition Newsletter has an interesting article about MAP Controlled Thermostats:

https://www.rockauto.com/Newsletter/


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## 73blazer (Feb 19, 2020)

Well I got my scan data back and mostly cleaned up in catia. I did a little more reinforcing around that smaller nipple that broke off. 
Needs a little more work, I had to get a buddy of mine to help me, my catia is a bit rusty. I should be getting some quotes for print this week. 










The scan tolerance is so high that you can see all the little pits and imperfections my piece had including the couple places I gouged it with my fingernail, so that all needed cleaned up in catia. 


Anywhere, here's an interesting aside. 
That center plate 07C-103-185-B behind that t-stat I told you guys about that was leaking as well every so slightly under the pressure test (and looked like it had been leaking for some time after witnessing where exactly it was leaking). The new plate is a D part and has reinforcing ribs on it. Apparently, it warps. It should spec longer bolts, but it doesn't, but I think there is still plenty of thread engagement.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

That scan looks good. When you get the new hose, are you going to scan the new coupling also?

The holes in the new plate look about the same depth as the old plate. 

There is a specification for how many threads on a bolt have to protrude from the other side when it's tightened to proper specifications using all hardware (flat washer, lock washer, nut, or similar fasteners, etc..).

I think it was two threads above the nut or past the nutplate or into a threaded hole. There is probably a similar DIN specification.


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## 73blazer (Feb 19, 2020)

53PL-50AAA-VW611BAN said:


> That scan looks good. When you get the new hose, are you going to scan the new coupling also?
> 
> The holes in the new plate look about the same depth as the old plate.
> 
> ...


The new plate is alot thicker. the main flat part is the same, but add the additional thickness of those reinf.ribs the holes run thru, and ...

I'm not holding my breath for the lativa hose. It's been over two weeks and nothing. He "forgot" to put a tracking on it, i'm not sure you can ship anything international without a tracking. 
If something does actually arrive, I have little faith it will actually be the right hose. Probably something generic alot of them guys think is perfectly ok to use with some modifications.


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## 73blazer (Feb 19, 2020)

Yeah, so in analyzing this part before I send it out for print, I cut a section through the original profile. (The red line in there)
The top side where it's leaking is pretty thin there. the bottom side of that same step down is nice and meaty, but their mold got thin up top there. 
So I'll add some more material to that step area there where it was leaking. 










So now that's what, I get to rename the part 3D0-122-291-D????


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## invisiblewave (Sep 22, 2008)

73blazer said:


> So now that's what, I get to rename the part 3D0-122-291-D????


Absolutely! Can you get the new part number included in the print??


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

73blazer said:


> The new plate is alot thicker. the main flat part is the same, but add the additional thickness of those reinf.ribs the holes run thru, and ...
> 
> I'm not holding my breath for the lativa hose. It's been over two weeks and nothing. He "forgot" to put a tracking on it, i'm not sure you can ship anything international without a tracking.
> If something does actually arrive, I have little faith it will actually be the right hose. Probably something generic alot of them guys think is perfectly ok to use with some modifications.


The time I ordered the NLA hood buffer from this Latvian seller, it took forever and a day and that was a few years ago. I can't remember if it had tracking. The hose may have been drop shipped which is why there is no tracking. If it's NLA the seller should cancel the order and refund the money. 

I ordered a left fog light grill on eBay from another seller from Latvia. That auction showed the actual part, but the order got canceled. The seller refunded my money and sent a message that the part was no longer available.


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## 73blazer (Feb 19, 2020)

I brought that step out a bit more and increased the fillet a bit to increase the meat in that area. I also brought the base of the smaller nipple up more to give that alot more support. 











Yeah, I'll put some txt on the housing when I finalize this. 

That latvia guy...just seems awfully suspicious that one latvia seller who's had that hose listed for a long time suddenly when asked says, oh, no it's not available. Then sudden this guy shows up with 3 with "1 sold in the last day" WHen I asked he responded too quickly, yes we have it. Then sends with no tracking, international. Not holding my breath. Besides, I like my D fitting much better now! And the Carbon DLS print method is no layers and in Cyanate Ester should be alot better than the original glass filled nylon 6 injection mold (if it even was tthat, I think this supplier used some kind of defective material as it broke down too quickly and turned soft from the antifreeze unlike the rest of the plastic fittings on the cooling system). There's lots of cyanate ester fluid manifold parts on spacecraft and aircraft. Auto doesn't use it because it's too expensive.


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## Phaetonlvr (Feb 26, 2013)

Excellent work, can't wait to see the final product!


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## 73blazer (Feb 19, 2020)

I got my original fitting back from the CT scan place and procedded to...saw it half. So I could check the profile along that oring housing to my scan/cad model. 
Scan is perfect. Profile matches, now improved with more meaty steps and fillets. 
But...look at how thin that original is at the last step before the main 90sweep! I'd say it was ate away, but from the outside?????
The root problem is the material of that thing, it's weird, soft, peel's like an orange. Seems to have absorbed the coolant and eaten itself. The discoloration of tthe parts in contact with coolant is odd too. All the other plastic coolant fittings are fine, not soft, no discoloration....not like this.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

Maybe it's a different material that's more flexible to allow it to have the clips and to "give" more over different materials like aluminum. 

On the other hand, I did find some similar fittings with clips made out of aluminum but they didn't have the correct hose attachments.

I noticed the fittings for the oil collection things were flexible enough to squeeze by hand to remove them (like squeezing a child proof cap on a medicine bottle). Those are probably a different material than the more rigid center fittings.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

53PL-50AAA-VW611BAN said:


> On the other hand, I did find some similar fittings with clips made out of aluminum but they didn't have the correct hose attachments.


It took me a while to find them but the ones I see on eBay today are aftermarket cast aluminum couplers from China. Since they are aftermarket, there is no way to tell if they have the same thermal expansion properties as the original plastic couplers.

For instance, I have read both good and bad things about aftermarket aluminum VR6 thermostat housings.


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## PowerDubs (Jul 22, 2001)

"Seems to have absorbed the coolant and eaten itself."


Very possible there has been mixing of various coolants over the years- some of which may not have been the right type or compatible with the others.


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## 73blazer (Feb 19, 2020)

Here's my finished part:










K5|Obsolete would be the name of the company I would create if I were so inclined to perform this service for others (or rather if someone were so inclined to pay the significant $$$ to have this done for them) since the name of my current company is K5|Computing
1A is K5's part# 1 Version A. It's VW part 3D0122291C (Actually improved version of that!)

It says Sept 3rd delivery, or possibly sooner


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## 73blazer (Feb 19, 2020)

PowerDubs said:


> "Seems to have absorbed the coolant and eaten itself."
> 
> 
> Very possible there has been mixing of various coolants over the years- some of which may not have been the right type or compatible with the others.



If that was the case I would expect all the plastic fittings in the cooling system to exhibit this condition, and none of the others I've inspected, have it. Just this one. All the other plastic in the cooling system is not discolored much at all and still hard inside and out. 
I believe the supplier used a defective material on this particular fitting.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

Your coupling looks great. Are you thinking of selling these? 


Isn't the coolant right out of the thermostat the hottest coolant in an engine? The thermostat outlet is probably also the hottest part on an engine. 

The other fittings and couplings are further away if only by a matter of inches. 

I would imagine the fittings and couplings after the radiators are probably in the best condition.

It could also be that it's a different material. Do you have a way to get the carcass tested to see what it's made of?

The fittings that don't disconnect don't have to flex so they could have been made of harder plastic. 

Those could even be replaced with metal pipes as long as they don't create corrosion. 

If we had access to VW engineering drawings we could find out what material was specified and if the coupling meets the engineering requirement.


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## 73blazer (Feb 19, 2020)

53PL-50AAA-VW611BAN said:


> Your coupling looks great. Are you thinking of selling these?
> 
> 
> Isn't the coolant right out of the thermostat the hottest coolant in an engine? The thermostat outlet is probably also the hottest part on an engine.
> ...


Even "hot" coolant shouldn't be above 130c. Well below the threshold for these. Automotives don't typically use exotic materials, they stick to a big list of what they know for cost,performance and warranty (longevity) reasons. Most fittings like that for that purpose are 15% glass filled Nylon 6 which is good to 200C and has great all around impact and tensile properties and it's perfect for injection mold and its cheap and Id be shocked if this was anything other than that. . I'm 90% sure that's what it is or what it was supposed to be. It's very difficult to 3d print nylon 6, so you don't really find it. Nylon 12 can be 3d printed...which is less heat (around 130c which is starting to push what you might see in adverse conditions) and less strong is out there, but even then the printers for that are layers and not really good for long term watertight objects. I'm having it done in Cyanate ester on a Carbon DLS machine (dls=digital light synthesis, it forms the resin in uv light and produces isotropic parts that are solid and layerless like injection mold). Cyante ester is good for 230c (and is slightly stronger than glass filled nylon 6). Some spacecraft have cyanate ester liquid oxygen tanks and plumbing fittings. Also well suited for acids, engine coolants, hydraulic oils, and a long list of other harsh chemicals. 
I had 4 done because 4 was pretty much same price as 1,2 or 3. I'll test it, if it works, Ill have 2 to sell if someone wants one. 
Remember these are only found on 2002-2005 BAP W12 "hot country" cars (those with the aux radiator)

I refuse to believe it's just time, it's old , it was exposed to hotter coolant. Nope, not buying it. All other fittings on the car I saw and got a look at inside, are perfectly fine. My 1989 Pontiac STE has nylon 6 fittings on it's coolant system, they're all in perfect working order. The plastic side tanks found on most vehicles alum radiators, nylon 6 glass filled. PLenty of late 90's and early 2000's cars with no problems there and if there is a problem 9 times out of ten it's the alum channels or the gasket between the alum and plastic. I can't remember the last time I replaced a radiator in a car. Pretty sure the supplier for this fitting screwed something up.


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## Phaetonlvr (Feb 26, 2013)

73blazer said:


> I refuse to believe it's just time, it's old , it was exposed to hotter coolant. Nope, not buying it. All other fittings on the car I saw and got a look at inside, are perfectly fine. My 1989 Pontiac STE has nylon 6 fittings on it's coolant system, they're all in perfect working order. The plastic side tanks found on most vehicles alum radiators, nylon 6 glass filled. PLenty of late 90's and early 2000's cars with no problems there and if there is a problem 9 times out of ten it's the alum channels or the gasket between the alum and plastic. I can't remember the last time I replaced a radiator in a car. Pretty sure the supplier for this fitting screwed something up.


Excellent work there! So I remembered that when I rebuilt the one W12 Phaeton I bought as a wreck 4 years ago, I had to change the upper coolant hose because the temp sensor was hit and cracked the slot for the temp sensor clip. Turns out I saved that coolant hose and just found it in my parts stash. That fitting is still rock hard inside & out and only has a little bit of orange discoloring on the inside. I agree that you must have had a fitting from a bad batch or some previous owner's mechanic did something to it. Btw, I think the material it's made out of is noted on the part, usually some 3 or 4 letter code.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

Phaetonlvr said:


> Btw, I think the material it's made out of is noted on the part, usually some 3 or 4 letter code.


I do remember seeing a code on a tiny VW part and it wasn't the part number. The parts person thought it was code for recycling which would also indicate the material used.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

73blazer said:


> I'm having it done in Cyanate ester on a Carbon DLS machine (dls=digital light synthesis, it forms the resin in uv light and produces isotropic parts that are solid and layerless like injection mold). Cyante ester is good for 230c (and is slightly stronger than glass filled nylon 6). Some spacecraft have cyanate ester liquid oxygen tanks and plumbing fittings. Also well suited for acids, engine coolants, hydraulic oils, and a long list of other harsh chemicals.
> I had 4 done because 4 was pretty much same price as 1,2 or 3. I'll test it, if it works, Ill have 2 to sell if someone wants one.


I remember you mentioning this. I'd want at least one. 



73blazer said:


> I refuse to believe it's just time, it's old , it was exposed to hotter coolant. Nope, not buying it. All other fittings on the car I saw and got a look at inside, are perfectly fine. My 1989 Pontiac STE has nylon 6 fittings on it's coolant system, they're all in perfect working order. The plastic side tanks found on most vehicles alum radiators, nylon 6 glass filled. PLenty of late 90's and early 2000's cars with no problems there and if there is a problem 9 times out of ten it's the alum channels or the gasket between the alum and plastic. I can't remember the last time I replaced a radiator in a car. Pretty sure the supplier for this fitting screwed something up.


I was just spitballing there, trying to find a reasonable explanation. I do have two of these so I have a vested interest to believe there is a plausible explanation for the failure. 

It also sounds like you know your plastics. 

Some plastic parts in the interior of my '77 Ford crumble in my hands if I dare touch them. The rim on the rear view mirror turned to dust when I tried to adjust it. When I took the driver's inner door panel off to fix the electric window switches, the door handle trim likewise crumbled where I touched it. I had to be very careful reinstalling it so it would stay in one piece. The rear window trim is missing because it fell apart in my hands. It's a 4 door so interior parts are not reproduced, especially window trim. It's green and I thought that might be a factor, but the instrument bulb holders also crumble if you touch them and they are yellowed white plastic. The instrument panel and the backs of the instruments are made of some harder plastic that doesn't crumble. I don't know if the parts that turn to dust are made of a softer, safer plastic or what the deal is. 

The interior plastic bits in my '88 Scirocco don't crumble but some of tabs on the outside parts did. It's led a sheltered life since new and that may be why the interior bits are not turning to dust. 

-Eric


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## 73blazer (Feb 19, 2020)

Phaetonlvr said:


> Excellent work there! So I remembered that when I rebuilt the one W12 Phaeton I bought as a wreck 4 years ago, I had to change the upper coolant hose because the temp sensor was hit and cracked the slot for the temp sensor clip. Turns out I saved that coolant hose and just found it in my parts stash. That fitting is still rock hard inside & out and only has a little bit of orange discoloring on the inside. I agree that you must have had a fitting from a bad batch or some previous owner's mechanic did something to it. Btw, I think the material it's made out of is noted on the part, usually some 3 or 4 letter code.


Yeah, it does. I dunno why I didn't read that before. 
PA66 GF30 meaning Nylon 66 (which is a Nylon 6 variant) with 30% glass fill.


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## 73blazer (Feb 19, 2020)

53PL-50AAA-VW611BAN said:


> I remember you mentioning this. I'd want at least one.
> 
> It also sounds like you know your plastics.
> 
> ...


I only know enough from working around some materials engineers in the OEM's I frequent. By no means am I a material scientist. I know enough to know, I don't know much. 
Plastics from the 60's and 70's are a totally different animal. Chemistry for them was in it's infancy and QA testing beyond initial function didn't really exist. Today they bake test parts on a car to simulate being left out in the desert for weeks and see if stuff warps or degrades, they just didn't really do stuff like that then.


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## 73blazer (Feb 19, 2020)

Still no lativa hose, it's well past "due" 

But I got my improved beefed up version 3d printed via digital light synthesis. Should be trying one out monday or tuesday. 
They look really good. Tolerances seem tight. This is about as close as you can get to cad.


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## PowerDubs (Jul 22, 2001)

That looks fantastic.

Good luck!!


Sent from my iPhone using Tapatalk


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## Phaetonlvr (Feb 26, 2013)

Looks great, can't wait to see it installed and in action.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

73blazer said:


> Still no lativa hose, it's well past "due"
> 
> But I got my improved beefed up version 3d printed via digital light synthesis. Should be trying one out monday or tuesday.
> They look really good. Tolerances seem tight. This is about as close as you can get to cad.


Your version looks great. Are you going to make more for sale?

I'd be down for at least two (depending on cost of course). 


I bought a few NLA Scirocco fuel hoses from the same seller. 

I ordered them July 31st and received them August 31st.

I also got an NLA Phaeton part from that seller before.


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## 73blazer (Feb 19, 2020)

Fitmant seems really solid. Clip snaps up and down just as it should (re-used my old clip). New O-ring fits perfect (I ordered new o-rings). 
Snaps on and feels tight on the old t-stat. SHould be installed and able to pressure test it later tonight or tomorrow. 
I like the way this fits. If it's functional properties are up to what the spec sheet says it is, this should be good!


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## 73blazer (Feb 19, 2020)

*Pressure test, Check!*

Holding 20+lbs for over an hour now, needle hasn't moved at all. IIRC the system pressure on these is 13lbs or so, so holding 20+ is perfect. 
The plate leak and obviously the fitting leak, are fixed!

Just need to put the intakes back on and fire this bitch up again. Between the two new sensors, two minor leaks and new t-stat, I'm hoping my original overheating problem, is solved.


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## Phaetonlvr (Feb 26, 2013)

Looking good :thumbup:


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## PowerDubs (Jul 22, 2001)

Love it!!!


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## 73blazer (Feb 19, 2020)

Well I got this buttoned up today. 
Got everything hooked back up proper, topped it off again with coolant and started it up. No codes! (well, the tpms system seems have to taken a crap from sitting)
The coolant hose fitting part, seems to work just fine! No leaks or issues there. (I also replaced the spark plugs, and upper lower intake gaskets and both pcv valves)

Went for a drive, and it stuck at 200 for 10mins or so while driving, and then started rising, went home let it cool a bit, reservoir empty. Ok
FIll it back up, run it with the cap off for a bit in different positions (front end up, tilted left, rightt, front end down..etc), fill it again, until it started expanding out over the lid, closed it off. Drive, 10-15mins 200 no problem, then starts rising. If you shut it off and wait about 1-2 mins, then turn it back on, its where it was for a couple 3-5 seconds then drops to 200 ( i know it didn't do this before). Drive, starts rising. 
Ugh.:banghead:
So all this, and still overheating. New t-stat, 2 new sensors and 2 minor leaks fixed. 
It does seem different than before, it would never stick around at 200 before, it would just blow past that and keep going up, very very slowly. This sticks at 200 for 10-15 minutes and then rises rapidly, like within 1/2mile it'll go from 200 to 240. 

I'm thinking (hoping) there is just still air in that system. I know your supposed to charge it with vas6096 vacuum charging thing. I also know it's a very complicated cooling system with multiple loops and keep in mind I did remove a bunch of lower hoses to drain it as I wanted to change as much coolant as possible. It's taken about 3.5-3.75 gallons I think system capacity from true empty is 4.5 gallons but I'm sure i didn't get it all out. I do get really good heat and that more or less will keep it at bay if I have it on full blast. WHich is a bit odd. Heater hoses are the highest part I think. 
Is bleeding this thing without vas6096 a royal pain for everyone? Never really had trouble bleeding any other car, just usually run it with cap off until the t-stat opens and watch it drop and you get air, top it off, and mabey keep an eye on it for a few days and...your good. Not this thing!
Guess I'll let it truly cool overnight and hopefully the reservoir will be really low again.


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## Phaetonlvr (Feb 26, 2013)

That's weird. I never have an issue with bleeding the air out of the cooling system of my W12s. I just fill the reservoir all the way, run the engine for a little while, refill, take it for a short drive then let it cool down all the way, usually overnight. I'll refill it in the morning and go on another drive and after another full cool down top it off. Then I check the level a couple more times after a drive. That's all that's needed, even when I had the system completely empty when I changed the alternator coolant line O-rings.


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## 73blazer (Feb 19, 2020)

I was blowing air into alot of lines trying to get all I could out when I drained it. I've not let it cool completely yet either, just 45mins or enough to get the cap ff without a spray fest. 
I'm hoping (praying) it's still low and has air. I can see one small bubble in my new fitting since it's translucent. And I can see when the t-stat opens the bubble disappears and comes back after it's cooled a bit and stopped gurgling. It was gurgling pretty heavy the two times I shut it off that says air. We'll see what's it's like in the AM.
If it's not air, I shun to think what it would be.


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## dlouie (Oct 31, 2008)

I just wanted to say this is an excellent thread and effort to keep our cars on the road! I have 4 3D printers and use them for creating all sorts of bits. Looks like a this is a perfect way to remanufacture parts in a variety of materials, metal included.

BTW, I bought a relatively inexpensive vaccum coolant filling tool from ebay. Vaccum filling is by far the easiest method to fill and not need to bleed afterwards. Well worth it!

Damon


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## Phaetonlvr (Feb 26, 2013)

dlouie said:


> BTW, I bought a relatively inexpensive vaccum coolant filling tool from ebay. Vaccum filling is by far the easiest method to fill and not need to bleed afterwards. Well worth it!
> 
> Damon


Damon, would you have brand name/link for that tool?


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## PowerDubs (Jul 22, 2001)

I would like to know as well.

I have a vacuum brake bleeder but nothing for the coolant.

As a point of reference- I have owned numerous 24v VR6, which is 1/2 of the W12.

I have substantially done work on them- swapped ported cyl heads, many cam swaps, etc- and they were always more air bubble prone than an old car.

I would typically- fill with cap open, start car till warm... level lowers, fill .. wait till it stops dropping... fill... drive car (important since the movement moves air along)... then open, top off- and importantly- I would reach and squeeze any hose I could reach, as aggressively and quickly as I could with the lid off and watch it burp.

The W12 is MUCH less access to hoses.... so tool would be good!!!











Sent from my iPhone using Tapatalk


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

When I swapped engines on my '78 Scirocco, it took about 3 days to burp all of the air out of the cooling system. Each day it would overheat and I'd have to top it up when it was cool enough. That was in the early 1980s on a very simple coolant system. 

My '88 Scirocco overheated on my dad when he drove it from my brother's garage to his garage when I was overseas.

The coolant was too low in the radiator so it didn't touch the coolant temperature switch and the fan didn't come on. 

The coolant temperature switch has to have hot coolant touch it to tell the fan to come on. 

You can turn the radiator fan on manually by turning on the A/C but that only helps if there is enough coolant in the radiator. 


Back to Phaetons...

Since I didn't know when or if the coolant had ever been flushed and filled on 7579, I had the dealer do it. 

I asked if it would burp and the service advisor said it wouldn't because they use a vacuum coolant filing system.

It didn't burp. It didn't overheat. 

I am pretty sure Eastwood sells coolant vacuum flush and fill kits. 

ECS Tuning or FCP Euro may also have them.


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## dlouie (Oct 31, 2008)

So I bought something like this:

https://www.ebay.com/itm/274464256386

I use my AC vacuum pump to pull the vacuum but it includes a fitting to use shop air to pull vacuum. 

This is how it is used:

https://youtu.be/IVyikhHE_38

There are others out there but the concept is the same.

Damon


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## Phaetonlvr (Feb 26, 2013)

That's a nifty tool and pretty cheap. I already have an AC vacuum pump so that's convenient. Thanks for the link.


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## 73blazer (Feb 19, 2020)

Yeah, next time. Yes, this system in particular really should be filled by vacuum charger. Hopefully there won't be a next time, but I'm sure there will be. Tools also take more time to arrive. In that time I can have the problem solved otherwise, perhaps. 

It was air, I just kept driving it letting it sit, then injecting coolant in the heater hose at the top of the cowl on the drivers rear of the engine, drive and go again. Last drive was 120miles mostly freeway @75mph and was pegged where it should be at 200 and never moved. So I think.......I'm good!. 
I don't actually think it was actually overheating either, I'd jump out with my IR gun when it was doing it and couldn't find anything much over 200 anywhere on the cooling system or block for that matter. I think those air bubbles hit the sensors and play games with how the computer interprets it. Physics says, you can't increase the thermal mass of 17l of coolant from 200 to 240f in seconds, and bring it back down to 200, in seconds like it was doing.


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## 73blazer (Feb 19, 2020)

FYI, I did end up getting a vacuum charger, one that has the same weird small dia quik-coups that my pressure kit had so it works with all my caps in the pressure kit, as the universal cone in the vacuum kit is fixed and would rather probably not work very well unless someone was holding it down. 
The pressure kit I have has caps for probably most anything (cap 6 fits Phaeton, even though it's not label for vw!), it also has reverse fittings to test caps to ensure they pop at the desired pressure. It also has three collapsing universals that are much better than the universal that came with the vacuum kit, but again, I got this particular vacuum kit because it had the same quick-coup connector so it'll work with all my caps and I don't need to use the universals. 
Oddly, the vacuum kit comes with a shop 1/2" shop air quick connector when 99% of all air tools, air compressors etc have a (I think it's 3/8") one (here in the us anyway), but it still has 1/4" npt on it's other side so you can simply unscrew that weird connector and install a normal air quick-coup available at any hardware or home store. I had a bin full of those. 

The pressure kit was $40 used on fleabay, and the vacuum kit was $40 new also from fleabay. 
Since you cannot truely "drain" the w12, i got mabey 4 gallons of ther 4.5 out, so I plan to drain this again and then I'll charge it with the vacuum filler. While the manual fill method works, it's a royal pita on this car requiring several heat cycles and injection into the heater hose at the top of the cowl. The vacuum fill is the way to go. 
Interestingly this vacuum, kit also says you can evacuate the system with it as well. It may just mean evacuate air, but when I pulled a vacuum with my hand pump vacuum pump on it it sucked fluid so..... I wonder if that would work to suck/create a siphon to truely drain this thing. If it did it'd certainly be alot more civilized way to drain this car. As I disconnected several hoses many of which were above other stuff which drips and runs and generally makes a giant mess because there's no catch pan big enough unless you covered the entire underbody which then you wouldn't be able to stand and undo hoses and fittings. 
One tip when using these vacuum fill, make sure you have a big enough container to hold all the coolant you wish to use, as moving the suction hose from 1 gallon container to the next is gonna suck some air even with using the valves on this thing, so it'd be best to find a clean 5 gallon bucket and poor all your new coolant into there then suction off of that for the final fill. 




























The 3d printed fitting is holding up just fine for now! 600mi on it, no issues!
So I'd have at least 2 to sell. I can make more obviously, but the min run is 4, so I'd need to make at least 4 more. I'd sell them at cost, $180/ea. I had to buy 4. So, while you might think 180 is alot, I paid for 4x180, plus the CT scan, plus the cad modeling to fix it up which I did, well, I owe a buddy of mine some cigars because my catia foo was a little rusty.They'd also include a new silicone o-ring which I spec'd and ordered, but you need to re-use your original metal clip.


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## Phaetonlvr (Feb 26, 2013)

Thanks for the detailed info on the pressure tester and vacuum kit. 

I'd take one of the coolant hose fittings if no one else is in urgent need. I don't really need it right now but with 4 W12s in my stable it might be a good spare to have just in case. PM me with details.


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## dlouie (Oct 31, 2008)

I have a resin 3d printer and would be willing to try to print for a member if the provide their own resin and post process themselves. Not sure what resin to use though.

Damon


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## 73blazer (Feb 19, 2020)

The resins required for a production quality under hood engine part are just not there for most 3d printers.

It needs strength, heat (and cold) resistance and water tightness. I have a buddy with an SLA printer and there was only one resin that would take the heat but it was a fairly weak material on top of that. And it was $300 for that resin which was enough to do about 2 parts. And it needed a special UV oven to cure it for hours as well. And SLA is still layered so water tightness is a problem, not guaranteed and especially over time which is why they still label SLA printed parts as prototype use only. And that resin didn't have near the tensile strength as the oem glass filled nylon. Not that there is alot of strength required but it is subjected to vibration and holds up those hoses so without it it's liable to crack over time. 
Any FDM printer would not make a water tight part due to the thickness of the layers (I think best any FDM can do is 150micron layers or 150 in X and 100 in Y & Z, something like that IIRC, Ijust was looking at all this a month ago..anyway fairly thick layers so not good for water tightness) and the materials there as well weren't up to heat best one was 80c spec or something in it's finished state. Mostly because those printer use heat as a method to print, so if you had a high heat part/material you'd need your printer around heating up that stuff to well hotter than it's design spec in order to just print it. 
SLS might cut it but materials there were also lacking for heat and strength, the best one was nylon 12 glass filled (oem is nylon 6 glass filled), nylon 12 was less strength and less heat (I think 100c was it's limit, and that's operating temp, so you need 130-140c min). SLS was just as expensive as the DLS method too. 

I'd have never printed this if it were not for the Carbon DLS process. it projects light thru the resin to print the part. Layerless and a true isotropic part. And the cyanate ester is good to 230c and stronger than nylon 6 gf. Those printers are $150k, so still an industrial printer which is why I had to use a service to get it done.


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## dlouie (Oct 31, 2008)

Yes, I knew that. Just offering however, I've also wanted to try this:





I've got a hot air station too so if someone needs to swap eeprom chips, I'd be willing to try.

Can the part be CNC'd.


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## 73blazer (Feb 19, 2020)

dlouie said:


> Yes, I knew that. Just offering however, I've also wanted to try this:
> 
> 
> 
> ...



CNC in alum or stainless was an option, as well as injection mold in nylon 6 gf, both these options didn't make sense until you got into 1000's of parts. For 2 or 4 or 6 it was $2500/part.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

Phaetonlvr said:


> Thanks for the detailed info on the pressure tester and vacuum kit.
> 
> I'd take one of the coolant hose fittings if no one else is in urgent need. I don't really need it right now but with 4 W12s in my stable it might be a good spare to have just in case. PM me with details.


I'd like one also.

-Eric


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## 73blazer (Feb 19, 2020)

Well, I'll keep those requests for parts in queue, i don't want to take anyone's money until I'm confident the part is up to snuff. It'll take some months. But I have them, you know where to look.

BUT

Mother puss buckets, I still have overheating!
Well, this is very different from before. The VCDS data before clearly showed it overheating.The sensors diverged and engine went up and rad output went down while ts-at duty went to 100% which is what led me to replace the t-tstat. 

Now, the VCDS data is pegged at engine output 120c and rad output 88c with t-stat duty at 60-70% . Peeged those numbers for 30-40miles at 75mph. 

BUT, the gauge on the dash is going all over the place. raises to 240F, message coolant overheating displayed, drops to 200F instantly. Raises to 220f, sticks, while driving constant 75mph for 20-30miles. Raises lowers. If I turn the heat on the dash lowers to 200, but the VCDS data on the two sensors, doesn't change at all!
So the dash is going all over, while seemingly responding to heat throughput, but the actual engine data says not overheating. And I can commensurate the engine data with my IR gun. If I stop the car when gauge shows 240F shut it off and get out with my IR gun I can't find anything except the exhaust over 200-210F anywhere under the hood. 

So...WTF is going on here??????? Computer problem? It definitely seems electrical. Fans are definitely working I can hear and see them ...they go up and down in speed (commensurate with the VCDS data, if engine out sensor reaches 125c engine out, fans go up in speed, temp comes down, fan goes down in speed). 
I tested the aux pump, i removed the floor on passenger side, found the relay (first one on the left) jumped it to batt power post under the hood, pump comes on you can hear it and feel it. (yes I put my hands on it). I tested it's relay, it's working. 
WTH is that dash gauge running off of? There's only two sensors and neither show what the dash does, the dash is going up and down while the engine out and rad out show constant temps! Is there some other sensor somewhere?????? I have great heat, so the heat pump in front of the drivers tire is working. I'm perplexed. It's not overheating, but dash says..it is, vcds data says, it's not. (which is very different from my original problem, where vcds data showed engine out clearly climbing to bad levels)


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## Phaetonlvr (Feb 26, 2013)

73blazer said:


> Well, I'll keep those requests for parts in queue, i don't want to take anyone's money until I'm confident the part is up to snuff. It'll take some months. But I have them, you know where to look.


Sounds good to me, I'm not in a hurry ... knock on wood 




73blazer said:


> Mother puss buckets, I still have overheating!
> Well, this is very different from before. The VCDS data before clearly showed it overheating.The sensors diverged and engine went up and rad output went down while ts-at duty went to 100% which is what led me to replace the t-tstat.
> 
> Now, the VCDS data is pegged at engine output 120c and rad output 88c with t-stat duty at 60-70% . Peeged those numbers for 30-40miles at 75mph.
> ...


I don't think there is any other coolant sensor. The instrument cluster talks to ECU1 which is the one that gets the two coolant temp signals. If I remember correctly there are multiple coolant temp readouts in the MVB list of ECU1 even though there are only two sensors, you can try logging them all to see if one is different. Of course the cluster itself could have a problem.


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## 73blazer (Feb 19, 2020)

Ok, STill overheating. But I logged data this time. It is actually overheating or getting there still. I was either looking at the wrong field before or who knows mabey I'm just losing it. 
But I logged it again. Same basic drive pattern and ambient as before. About 30-40miles 

Here's original problem as posted before:









Here's after new thermostat, two new senders. 









So before, clearly I had diverging lines with t-stat calling for wideopen and staying there. Now engine out and rad out keep going up rather in paralell with a mostly constant delta. That says, not enough water is getting to the radiator. 
The other thing is, see that dip in the second graph, that's me turning the heater on full blast, that runs it's own pump and obviously own radiators (heater cores). So blasting the heat can somewhat control it if the ambient is low enough. I was getting lucky last week because ambient was 50F degrees, last couple days it's been 70-80F degrees. 

So it seems not enough water is passing thru the radiator. I guess I could have gotten a bum t-stat, but probably unlikely. Perhaps my radiator is plugged up? Well, if I shut the car off, the after-run pump runs and the fans are running, if I give that 1-2 minutes, then turn the car back on, the temp drops instantly to 200F for 3-4minutes. So, some water is passing. Main water pump perhaps? I have a hard time believeing that one because if that was failed I don't think you'd make it 10miles let alone 40. Unless, I think someone said those plastic impellers can kinda spin but not fully? Do we know the common failure modes for these w12 water pumps?

I'm kinda ready to just throw a radiator and water pump at it. Not sure what else to do. 
I'm also thinking it may have been this way when I bought the car since I bought it in February and drove it 2-3000miles in march/april/early may when it 20/30/50 degrees I think that was just enough to keep it under control . But rise to 60-70-80f outside when I first saw the problem in June after not going anywhere for most of may, then it was overheating.


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## Phat One (Jul 10, 2009)

I have a V8 so not sure about W12s but the water pump impeller is metal on V8, and solid, no way the impeller will break. Only thing that might happen is it seize up
Graham


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

The part number is 07D121008A.

I don't know what the Genuine VW one looks like. VWOA doesn't show a photo of it so I checked eBay.

It doesn't matter what the Genuine VW pump has because we don't know if it still has the original pump in it. 

Most of them on eBay seem to have metal impellers. 

This one has a metal impeller:

https://www.ebay.com/itm/For-Audi-A...152576&hash=item5418ec05d8:g:Z4IAAOSwj6lb8TSz

This one has a non-metal impeller:

https://www.ebay.com/itm/One-New-Me...921940&hash=item41c61961c3:g:YyQAAOSwtoVbNIFN

-Eric


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

Forgive me if you mentioned this before.

Did you try adding water to the radiator itself through the top hose?

Is there steam coming from under the hood? 

I have the Bentley manual open right now. 

To paraphrase, these are the instructions:

Open a lot of hoses to drain it. 5 of them in fact. 

Make sure the coolant is ready. Mix it with water. 40% to 60%. Lower and higher percentages and the frost protecti0on and cooling effectiveness will be reduced. 

They have a chart showing 40% and 50% coolant and the temperature protection. 

Reconnect all hoses and clamp off the hoses to the auxiliary expansion tank using hose clamps. I think they mean to pinch the hoses shut with pinch clamps. 

Fill coolant circuit using VAS 6096. 

It has an arrow pointing at "Operating instructions for cooling system charge unit VAS 6096" but the instructions are not linked. 

I have no idea what the instructions for the VAS 8096 say but I'd imagine they are similar to directions for other vacuum coolant flush and fill systems.

After filling the system, they say to loosen hose clamps to the auxiliary expansion tank. If I am correct that they meant to pinch them off, then this means to remove the pinch clamps. 

Then the directions say to allow engine to idle until upper coolant hose at radiator is hot.

The final paragraph says to check coolant level and top off if necessary. If the engine is at operating temperature, the coolant level must be at max. If it's cold, the coolant must be between min and max marking.


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## Phaetonlvr (Feb 26, 2013)

73blazer said:


> So it seems not enough water is passing thru the radiator. I guess I could have gotten a bum t-stat, but probably unlikely. Perhaps my radiator is plugged up? Well, if I shut the car off, the after-run pump runs and the fans are running, if I give that 1-2 minutes, then turn the car back on, the temp drops instantly to 200F for 3-4minutes. So, some water is passing. Main water pump perhaps? I have a hard time believeing that one because if that was failed I don't think you'd make it 10miles let alone 40. Unless, I think someone said those plastic impellers can kinda spin but not fully? Do we know the common failure modes for these w12 water pumps?
> 
> I'm kinda ready to just throw a radiator and water pump at it. Not sure what else to do.
> I'm also thinking it may have been this way when I bought the car since I bought it in February and drove it 2-3000miles in march/april/early may when it 20/30/50 degrees I think that was just enough to keep it under control . But rise to 60-70-80f outside when I first saw the problem in June after not going anywhere for most of may, then it was overheating.


Did you check the serpentine belt and belt tension? Maybe the tensioner is getting weak and is letting the belt slip on the water pump pulley? The water pump is a lot easier to get to than on a V8 ... one of the few things that are easier on the W12 

If you do decide to replace the radiator be prepared for a long wait as there are currently none in the US but at least there is stock in Germany. The W12 uses a different radiator than the V8, essentially the difference is that the radiator core is thicker. 4 years ago when I rebuilt a salvage W12, I needed to replace the damaged radiator but none were in stock in the US even back then. I ended up buying the only aftermarket W12 specific Silla radiator that was readily available. That one was a lot lighter than the original but has been holding up surprisingly well over 25k miles. I was going to replace it once I got the OEM replacement radiator but didn't have to yet.


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## 73blazer (Feb 19, 2020)

I have a new beck/arnley metal impeller water pump.
This water pump I have to say looks kinda wimpy for a 400+hp engine. Small dia. My 110hp 2.5l iron duke 4cyl gm motor had a bigger pump on it. 

So water pump is easy huh? Book says font bumper off, set rad into "service position" and access pump? Is that the way of it? I should probably replace the belt well I'm at it just for fun, since it'll be easier to access then? Although the PO said it was just replaced during his 4 month tenure.


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## Phaetonlvr (Feb 26, 2013)

That's the correct procedure. If you are comfortable with taking the front bumper off then it's not a big deal.

The pump really is that small, I was surprised too when I first got mine. Btw, I would also get new water pump mounting bolts if they are not included with the pump.


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## 73blazer (Feb 19, 2020)

Well, comfortable is a subjective term. It needs done, i have the proper tools, i've read the remove bumper threads, I can do it. Do I want to, not really, but..

Someone had it off for something at some point, the drivers headlamp is loose and not secured properly and vibrates which is rather annoying at night, and the drivers headlamp washer pops out as expected, but the washer fluid just comes out from under that front nozzle area and not thru the nozzle, like the hose isn't connected, so I'm hoping it'll give me a chance to correct those problems.


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## Phaetonlvr (Feb 26, 2013)

The first time taking off the bumper cover can be intimidating for some but if you follow the instructions closely it's pretty straight forward, there's a step-by-step post in the FAQ section. You will definitely find some surprises once you have the cover of. Most of mine had broken bumper guides, some to the point of being unusable so be prepared for that. The three bumper guides are still available new, I think around $40 each if you buy online. The headlight washer issue is probably a disconnected hose.

The headlight will probably be a broken off mounting point, usually the one in the back is the one that goes kaput. Good news is that it can usually be epoxyed back on and be sturdy.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

Full disclosure: I haven't removed the front bumper cover yet because of the two person rule. 

I will probably use two boxes to support it equally when I do remove it.

The rear bumper cover is no problem alone. 

If you aren't in a hurry, you could buy all new hardware and clips. 

By "hurry", I mean if it's not your daily driver so you can take your time and only take the bumper cover off once. 

The Bentley says that all hardware needs to be replaced each time. I take that with a grain of salt, but do buy new if I have time. 

Usually it's only the plastic clips and "bolts" that really need to be replaced. 

The spoiler has plastic fasteners that hold it to the underbelly pan. Those usually need replacing. They look like Allen head screws but the heads pry up. 

They are more like reusable rivets. VW (and probably other makes) use them all over their cars. 

I replace the hardware if I have new hardware but save the old serviceable hardware. 

Most of the visible front bumper hardware on 7579 is corroded so I got all new hardware for when I swap the bumper cover.

I think ECS tuning had the best prices but it may have been eBay. 

ECS Tuning had the hardware in connected baggies. They are like a string of clear sausages with a single bolt in each one.

You could also get the guides ahead of time. If you have time you could just wait and see which need replacing. 

I printed out the parts diagram and put refence numbers for the hardware on the diagrams. Then I put corresponding numbers on the hardware bags. 

Good luck.

-Eric


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## 73blazer (Feb 19, 2020)

I'm starting to dislike this car more and more. 
Really, replace hardware? That is total BS if that is required. Aside from some special torque to yield bolts in high engineering areas like suspension, that's completely absurd. Mabey if it's rusted out or something, ok I get it, but replace for the fun of it...poor engineering if that is the case. Design your fasteners better! I can see some use once fasteners in places you never expect to be removed, but use once fasteners in an area of the car that is purposely designed as a service procedure to access lots of other things like lights, washers, water pump, belt, radiator etc...you don't use those there. 
Probably should have never sold my 2004 GTO, 190k mi, running fine, far better reliability than this car. I wonder how the Phaeton would fair in a good 'old fashion demo derby, because if **** keeps going this way, that's where I'm headed with it.


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## Phaetonlvr (Feb 26, 2013)

It can be frustrating, no question. I'm suspecting that the previous owner might have known about the issue and decided to move on instead of dealing with it. My little fleet of Phaetons has never stranded me in the last 7 years that I've owned them, they are pretty reliable especially at their current age. The only thing that got me close to stranded was a dying primary fuel pump but that was easy to work around because of being able to make the secondary one run permanently. They do throw fault codes here and do require regular maintenance.

I don't think there is any actual need to replace any of the fasteners on the front bumper cover, they can all be reused. The water pump mounting bolts might not be required to be replaced but I do that just so I have new ones in there that are not rounded off and in case of a water pump, they do get a lot of high heat cycles. The WP bolts on my classic Cadillacs are also known to weaken with time so they always get replaced also.


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## 73blazer (Feb 19, 2020)

Front bumper cover is off. That was actually fairly easy. About an hr. 
The 2 screws you need the long extension for were not there, so, some hack re-assembled this. 
The left headlamp washer indeed was just, the hose was not connected. Now why would that be??????? It positively engages and clamps on, it's clip isn't broke, I can'tt pull it off witthout releasing the clip, so someone took it off, why?

Anyway, enough fun for one day. I actually found the t10093 carrier guide pins on fleabay for $10. I gather they're not entirely necessary if you can manage to hold the carrier in some fashion, but, for $10...i'll try 'em .
Holy moly, god forbid if you get in a wreck with this thing, it's packed under there on each side!
I do like how there was just two electrical connectors for the front cover, that was nice, I was totally expecting each parking sensor, fog lamp, side lights to be separate connectors you'd have to disconnect. That did make it easier. They did some things right! Of course, whoever took this off before, broke the big connector and it was half loose. Very nice. I hate hack work. I don't mind jury rigs as long as their strong, but obviously it was a first time VW person, because the connectors are very easily disconnected if you know how, but if you don't know how, they're easily broke.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

I can relate to all of that. 

The right headlight washer on 7579 was attached with baling wire.

I have not removed the bumper cover but I was able to remove the baling wire through the opening. The clip that is supposed to be there is very inexpensive so I bought that for when I replace the bumper cover. The bracket under the right side of the grille is missing. There is nothing to hold the bumper cover screw. The left fog light grille was held on with a zip tie because that screw hole was broken out. 

The right headlight looks newer than the left headlight and its controller doesn't work. The bumper cover is also askew because somebody didn't line it up correctly. The right front fender is also not lined up quite right. 

It was hit in the right front but the accident didn't make the Car Fax. I guess whoever had the accident "repaired" it him or herself.


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## Phaetonlvr (Feb 26, 2013)

73blazer said:


> Front bumper cover is off. That was actually fairly easy. About an hr.


After the first time it's going to be even faster, it's really not a big deal to remove it.



73blazer said:


> The left headlamp washer indeed was just, the hose was not connected. Now why would that be??????? It positively engages and clamps on, it's clip isn't broke, I can'tt pull it off witthout releasing the clip, so someone took it off, why?


Somebody removed the bumper guide that the washer is attached to but instead of removing the one Philips head screw they unplugged the washer.



73blazer said:


> Anyway, enough fun for one day. I actually found the t10093 carrier guide pins on fleabay for $10. I gather they're not entirely necessary if you can manage to hold the carrier in some fashion, but, for $10...i'll try 'em .
> Holy moly, god forbid if you get in a wreck with this thing, it's packed under there on each side!
> I do like how there was just two electrical connectors for the front cover, that was nice, I was totally expecting each parking sensor, fog lamp, side lights to be separate connectors you'd have to disconnect. That did make it easier. They did some things right! Of course, whoever took this off before, broke the big connector and it was half loose. Very nice. I hate hack work. I don't mind jury rigs as long as their strong, but obviously it was a first time VW person, because the connectors are very easily disconnected if you know how, but if you don't know how, they're easily broke.


The T10093 tool is nothing else than 2 M10x1.5 Cap Bolts, 6.5“ long and with a plastic ball over the bolt head. What I had happen once is that the nut that the tools screws into, broke loose and made the lock carrier sag. That nut is only spot-welded to the frame so I always use a second nut so there's a nut on both sides of the frame to ensure the bolt stays in place.

Don't you love dealership mechanics  My V8 that I bought from the original owner, was dealer maintained since new and the amount of shady work and missing fasteners on that car was astonishing!


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## 73blazer (Feb 19, 2020)

Mother puss buckets. So I get back to this after being at a customer for 3 weeks. 

So I get the lock carrier in the service position, no problem. 
Get the belt loose.
Remove the pully.
So, WTF are those bolts holding the pump to the block? They're not torx or allen. It's some splined bolt I've never seen before. 
I tried a 5mm allen but I think I just striped some of those splines off one bolt.:banghead: (yeah, that was dumb of me, i kinda knew I shouldn't have done that, I may have just created a really big problem)

No special tool listed for those things, and I've never seen them before. 

Part# N10531402









Apparently the tool you need is triple square bit set. Never run into these before. Ish...more tools....


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## Phat One (Jul 10, 2009)

Yes, it's a triple square (12 splines)


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## Phaetonlvr (Feb 26, 2013)

Triple Square or also called XZN, there are some reasonably priced bit sets on Amazon. I have a set from Capri Tools and they are pretty good and are only $24. There are a few of those triple square bolts on the Phaeton, the most common one being the one for the front strut top mounting brackets.


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## 73blazer (Feb 19, 2020)

Yay, so I chewd up the one with my stupid allen head try. I figured 20nm, shouldn't be much. Ok, that was my fault. 

I went and got the tool, the local auto parts store had a set in stock.
Two of the other three stripped out. I got one out normally. 
Why they f- would they use these here. Seems completely stupid. Great. Now what. I can try my weld a nut on the front trick. drilled is going to be difficult even with a 90 degree attachment. Just f-ing great. One thing after another with this thing. If I work at it, mabey I can have it holed up for a whole year!
My guess is I'm gonna end up taking the whole lock carrier off so I can drill them out normally from the front.


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## Phaetonlvr (Feb 26, 2013)

Swing the lock carrier out on the RH side by using an engine hoist or something similar. You already have the coolant hose disconnected so might as well disconnect the hood release cable and the cooling fan wiring and you should be good to go. I would keep the LH side in the service position so you don't have to disconnect the AC hoses from the condenser.


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## 73blazer (Feb 19, 2020)

I was able to get the water pumps bolts out by removing the lower fan wiring and h/l washer pump hose across the front bumper (of course that y cracked on the passenger side, nice) the lower hose was already disconnected, remove the upper hose also.
Then just getting the lock carrier out another few inches was all that was needed to get my drill with the 90 attachment in there with some machine length (short) bits, drilled the heads out a bit and put in my Irwin hex exactors in with enough room to get a little swing on a hammer to get them seated nicely and the bolts came out. The extractors are nice if you get a good clean shallow hole they bite nicely so you don't need to drill the whole damn thing out and hope you can vice grip the rest of the stud out.
I have this set here:

























The bad news.
There does not appear to be anything wrong with that water pump. The plastic fins all in place, kinda brittle you touch them they distengrated, but they were all there. I grabbed the impeller and the input shaft with two sets of pliers and could not get them to move opposite, so I don't think the impeller was slipping on the shaft. 

So, perhaps something was going on when it got warm, butt if it's not the water pump, I'm a little bit out of ideas. I did order a new belt tensioner today, just for ****s and grins. Perhaps something was going on with that when it got warm. It didn't seem to take much effort (unlike my american cars tensioners) to move it to get the belt off.


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## Phaetonlvr (Feb 26, 2013)

Glad to hear you got the bolts out. The tensioner should give you a good amount of resistance, I think it's an oil-type tensioner (I know on the V8 it is), not like the spring-type on the older American cars.


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## 73blazer (Feb 19, 2020)

Phaetonlvr said:


> Glad to hear you got the bolts out. The tensioner should give you a good amount of resistance, I think it's an oil-type tensioner (I know on the V8 it is), not like the spring-type on the older American cars.


I was able to move the tensioner with just a std length 3/8 ratchet handle. I have a piece of rigid conduit I slip over that handle usually for such duties, like on my LS1 motor in my '04 GTO, spring tensioner requires a long length handle to move it. That's what made me suspect of it, seemed just a bit too easy. 

New belt too. BTW Rock auto currently has a Dayco 6071012 on closeout for $4.58. $45 at any other store.


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## Phaetonlvr (Feb 26, 2013)

Will be interesting to see how the new tensioner feels once you get it, maybe that was the problem all along?!

That's a great deal on the belt. I know there is one incorrectly listed Continental belt out there that does not fit, I think it's part # D4071010. I've used the original VW belts in the past but they are around $90 new.


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## 73blazer (Feb 19, 2020)

Still waiting on my new belt tensioner. But I got new headlight washers each had a ball missing from one of the two eyes and you could see the housing around the missing eye was cracked. Put the new water pump in, new belt, when I get the tensioner, should be just a few hrs to put it back together and.....will it be fixed???

I did use my new vacuum coolant charge kit on my '14 Chevy Volt w130kmi. . The on-board charger went bad and it's water cooled, put a new charger in and vacuumed charged that loop...ran the bleed procedure (basically just runs the electric pump up and down in RPM for 1/2hr) and no issues! So I should be able to recharge the W12 without issue this time around.


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## 73blazer (Feb 19, 2020)

Belt tensioner arriving today, I should be able to get this back together tonight. 

Any bets?
So I'll have replaced both sensors, thermostat, main water pump, belt, belt tensioner (full deal w/pulley).

So, if it still does it.....ECU?????? The new thermostat & sensors did seem to change the nature of the issue if you look at the graphs, but end result, was overheating still after those.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

73blazer said:


> Belt tensioner arriving today, I should be able to get this back together tonight.
> 
> Any bets?
> So I'll have replaced both sensors, thermostat, main water pump, belt, belt tensioner (full deal w/pulley).
> ...


If that doesn't work, you could try swapping the ECUs. One handles or monitors some of the cooling components. The other ECU handles or monitors the other cooling components.


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## 73blazer (Feb 19, 2020)

53PL-50AAA-VW611BAN said:


> .... you could try swapping the ECUs. One handles or monitors some of the cooling components.


Are they the same? You mean you can just swap the two that are in there like MAF sensors? Or do you mean swap the one that does cooling duty with a new/used/different one?


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

73blazer said:


> Are they the same? You mean you can just swap the two that are in there like MAF sensors? Or do you mean swap the one that does cooling duty with a new/used/different one?


According to the Study guide they are the same. The connectors are wired differently to tell them apart. 

Both do cooling duty. they just handle different parts of the cooling duty. 

If your cooling problem shows up as a fault in one of the ECUs, and the fault is still there after swapping them it's not the ECU.

I don't think the fault will switch sides because each ECU handles different coolant duties. 

Maybe a generic scanner would show a generic cooling fault that switches sides but I think you will see either no fault or a different fault on the other side. 

Carful opening that box. I haven't opened mine but according to the thread, it's hard to get the box to seal correctly. 

I haven't seen that box. Apparently it's under the auxiliary coolant reservoir. 

He also said it was hard to reinstall the shift knob and I have no problem with that. 


Have you been clearing faults each time you change something?


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## Phaetonlvr (Feb 26, 2013)

73blazer said:


> Are they the same? You mean you can just swap the two that are in there like MAF sensors? Or do you mean swap the one that does cooling duty with a new/used/different one?


The two ECUs are identical on the same car (I believe they are keyed to the Kessy like the instrument cluster and steering column controller), which plug they are plugged into determines what they do. 

I'm curious to hear if the tensioner is the cause, not sure what else it could be at this point.


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## 73blazer (Feb 19, 2020)

Tensioner is on, just piecing it back together at this point. It was a little harder to turn than the one I took off, but not alot. I could still turn it with the std ratchet handle, but somewhat more effort involved. I used my real 'tensioner' tool to actually do it as holding it while trying to finangle the belt on is alot easier that way. 
That tensioner is just a spring inside, no oil, nothing special. Just a little spring loaded mini shock assembly. 
Can't imagine doing that belt from below with nothing else removed, I can see it *could* be done, but it's certainly alot easier when the carrier is far out like I have it!


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## PowerDubs (Jul 22, 2001)

On Dennis’s W12 Phaeton- he had a thermostat error. Replaced the thermostat- problem persisted.

We checked the wiring, all the way to the ecu- it was fine.

Knowing the ecu are exactly the same- but react different depending on location - I swapped them, and the problem never came back. 

That was several years ago. There is a thread here somewhere when it happened.


Sent from my iPhone using Tapatalk


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## 73blazer (Feb 19, 2020)

No sale.

Same exact condition.

You can drive 30-40mi no problem, then suddenly, it wants to start rising. 

WTF. 

Praytell where are these ECU's, do you have to tear apart half the car to get at them? It sure seems electronic to me. You can't go 30-40miles with a bad pump, rad, fans, t-stat,etc. The first 30-40mi is perfect, needle sticks right below the 200 tick, set cruise at 75mph, 30-40mi, temps right at 200 the whole time....suddenly the needle waivers and starts to rise. 

Is there a way to program the ECU to do a wide open t-stat all the time (like if your having these issues on a SBC you just go remove the t-stat from the housing)
I supposed I could have gotten a bad sensor or bad t-stat. I guess I can try swapping the sensors again. I dunno. Starting to get a little degraded on this one. 

On a positive note, the vacuum fill sure is alot easier and cleaner! Pull vacuum, flip valves, let it fill. I repeat a 2nd time just for fun, but end of procedure bottle was pretty much at the level it should be. I like it.
I was also able to put those long reach screws in that were missing on the front fascia (the ones you have to go in through the wheel well with a long reach torx to remove). Those drag that edge to a close against the fender, alot cleaner look! ANd my headlight washer issue fixed, that was easy, whoever took the fascia off last time seems to have just forgotten to hook the water line back up to that side.
But, it's all moot, if the stupid thing just wants to overheat and you can't drive it.

New water pump, water pump bolts, belt, belt tensioner, both sensors, t-stat, no leaks, hold 20lbs pressure and 25hg vacuum for over an hr without moving at all, checked rad and fans all working fine. I've not replaced the aux pump but it's on another side loop and shouldn't come into play while on cruise control at 70mph anyway. I've tested that aux pump (removed the pass. floor, removed it's relay, jumped it from the relay power terminal, works fine, checked relay, it's fine. ) 



53PL-50AAA-VW611BAN said:


> Have you been clearing faults each time you change something?


I don't get any faults. No codes, nothing. Well I'll get a code if I let it rise too high.


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## PowerDubs (Jul 22, 2001)

The ECUs are under the wipers/windshield


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## 73blazer (Feb 19, 2020)

I supposed possibly it's the radiator. On it's very simple basis, it acts as though there's not enough cooling capacity. If you turn the heater on it definitly helps it, so just adding an extra heater core seems to help it. My gut seems to point to electronics but I can't seem to explain how electronics could 'block' anything. The t-stat will open mechanically at 210, so it should never go over that, it will. Electronics can't really control the cooling system, only enhance it. 

I'll gather some more data today. I found the VAG self study guide that explains how you can tell if your getting a "calculated" cooling sensor reading or a real one, it's still possible it's not actually overheating, as I can take my IR gun and I can't really find anything nominally above 200F except for the exhaust. If somehow it's mis-calculating, perhaps I did get a bum sensor....I dunno. 

Where's these ECU's? I can't see them under there. Behind the 2nd expansion tank and slightly outboard is a black box with fuses in it. Under the 2nd expansion tank it just seems like coolant hoses and other BS. There's something behind it more toward the center. Drives side I don't see anything. 
I have the manual but not finding anything in it on how to remove and replace an ECU. I looked up the part and have a general idea what it's supposed to look like. Are they buried way under there?


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## dlouie (Oct 31, 2008)

Any chance you can get your hands on a thermal imager? You should be able to visually see problems the radiator or other parts. We use them all the time in building diagnostics. 

Damon


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## Phaetonlvr (Feb 26, 2013)

Very startling, sorry to hear you still have the same issue. 

Here's the procedure for the ECU removal from the manual for the W12, page 211:

Removing
– Switch off ignition.
– Remove plenum chamber cover.
– Remove windscreen wiper motor on right side ⇒ Electrical
system; Rep. gr. 92 ; Windscreen wiper system .
– Remove gearbox control unit.
– Release connectors from control unit and pull off.
– Control unit can now be removed.
– To install, reconnect connectors to engine control unit and lock
in position.
– Remove windscreen wiper motor on right side ⇒ Electrical
system; Rep. gr. 92 ; Windscreen wiper system .
– Install plenum chamber cover.

I've only done this on a V8 before which also has it in the same location. It's really buried all the way back behind and under the windshield.


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## 73blazer (Feb 19, 2020)

Is this of any use? I went for a drive collecting VCDS data, what happens is it runs up like the previous graph shows, engine out stays pretty much at 105-108c, rad out pretty much stays at 70-75c. Oil temp...i watched carefully...it's at 90c or so when engine temp reaches operating temp (105c)...but it keeps rising very slowly to 100-105-when it gets to about 110-114 (240f on the dash dial) that's when the engine out coolant just starts going up. 

Where's a normal W12 oil temp stabilize at at highway cruise on a 65-70degree day????

Really at a loss. Again you can shut it off for just 30s or so, turn it back on and within about 20-30s it drops all the way down to 105c again and the fans go full tilt, but then starts rising slowly immediately with the fans dropping down to a lower more normal speed. Fans are on low during the afterrun when it's off. 
It's like there's blockage. 


I found the ECUs, yeah, they're reallllly buried back under there, but, accessible. I just swapped them and will finish putting the wiper motor back in a bit later today and take her for a ride. 

Why do mine have white out on the revision letter with some handwritten stuff on them?


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

I _believe_ the engine ECUs are in the same box as the W12 transmission controller.

Skip to post #79:

https://forums.vwvortex.com/showthread.php?1609467-Retrofitting-Paddle-Shifters-to-a-Phaeton/page4

Edit: I see you found them. Was this correct?

I myself have no idea why somebody would manually mark up the ECUs.


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## 73blazer (Feb 19, 2020)

Remove wiper arms, remove wiper bay cover thing, remove cowl (this was actually fairly difficult???!) , remove passenger wiper frame/assembly/motor. Unscrew aux coolant expansion tank and flip to the side (no need to disconnect) . Then you can get at the controllers. 

The transmission controller is first in it's own box, remove wires from top, remove top, tilt back, pull out trans controller, pop harness off top, remove controller, remove box. Then the two ecu's are in an open cage behind there. You have to remove the top part of that cage, then pop each controller out and remove the harness off the top of them. Not terribly difficult, worst part is leaning that far over the fender to get your hands and arms back in there.


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## Phaetonlvr (Feb 26, 2013)

Not sure if that is any help because my W12s are all 2004s. Three of them have suffix C ECUs while the early production one (pre-Premier Edition) has suffix AB ECUs. Maybe those are not original to your car and were recoded when installed? What part # does the controller report in the VCDS scans?

I can drive one of my W12s to work today, about 22 miles and outside temp is about 68F. What MVBs do you want me to log?


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## 73blazer (Feb 19, 2020)

Awesome. Thanks!

Log engine gr 130, you can do 131,132,134 as well, but alot of it is dup data. 
130 shows the three most important what my graphs above show. ENgine output temp, rad output temp, and t-stat duty cycle. The others show commanded engine out temp and a few other interesting but not sure of their relevance. 

See if you can note trans temp too I dunno where that one is, that's one idea is if something else is overhwhelming the radiator with heat like the trans cooler if that's in front of the thing no idea, was just thinking about it.


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## Phaetonlvr (Feb 26, 2013)

Sounds good, will get that data to you later tonight. Send me your email address in a PM so I can send you the log file.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

Both of my 2004 Phaetons have 07C 906 018 C ECUs according to VCDS.


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## invisiblewave (Sep 22, 2008)

Phaetonlvr said:


> Not sure if that is any help because my W12s are all 2004s.


Admitting you have a problem is the first step....:laugh:


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## Phaetonlvr (Feb 26, 2013)

invisiblewave said:


> Admitting you have a problem is the first step....:laugh:


Not a problem as long as they are running  One is a parts car though.


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## 73blazer (Feb 19, 2020)

Well ECU swap didn't change a thing.

So What I did manage to observe doesn't bode well.

Drove for a while, it starts going up after 20-30 miles as usual. 
I go home, watch it carefully while IR reading various places. The input (pass) side of radiator side tank is 165-170f while the gauge/engine out reads 230-240f. I can IR gun the output sensor directly it is about 230-240f. Output side of radiator side tank is 75-80F. If you let it go until the temp reaches 250 or so, the rad fans go to 95% duty cycle full on, input side of rad is 165 output is 65.The output side is commensurate with VCDS reading. So is the iengine out temp at least at the sensor itself on the back of the block when I get my IR gun on it. So sensors I think are OK. I think the radiator is fine, but somehow.. hot engine .water is not reaching the radiator. So....how could that be?
I was half ready to throw a radiator at it but it seems the radiator is capable of a large delta and that hot water is just not reaching the radiator.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

Does it get that hot at home or only when you are driving?

Do you let it warm up at home? Have you tried idling it at home until it heats up?

Mine get hot enough during scans for the engine fans to come on. 

Maybe a hose has a blockage or a previous owner connected the hoses wrong. 

You can point the IR thermometer at both ends of the hoses to see if a hose has different temperatures on each end. 

Have you tried revving the engine at home to the same RPMs as when you are driving?

Maybe the engine twists at higher RPMs and collapses a hose or something else happens at higher RPMs. 

Maybe a hose collapses on its own at higher RPMs or after it warms up. 

Is there something that blocks the radiator when you are driving?


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## 73blazer (Feb 19, 2020)

SO here's a drive from yesterday on my car over about 30miles. 









Here's Stephan's Drive from yesterday same data:









ANd here was my original problem before I did anything drive











My Original problem seems to have a t-stat that works initially but stops working 
Clearly the change og t-stat and sensors did something on my car. But now it seems the t-stat is not working at all. 
Stephans car clear shows t-stat cycle and rad output temp goes up, and there's a clear cycle there. 


From last nights observations where I can IR gun the input side of the radiator and it's basically not getting hot water. During the afterun it does and I get a big delta. If I restart the car right away and tthe fans come on full, I get the same delta Stephans is, so I don't think a radiator is gonna help. 
So either I have some blockage somewhere in the system, or perhaps I got a bum t-stat? Blockage seems a little unlikely as in my original problem shows at least initially t-stat opens and I get a increase in rad out temp. Now it appears I get nothing or next to nothing to the radiator. Which is commensurate with turn on heater and and I can somewhat control it if ambient is low enough. How likely is a bum t-stat out of the box. I know on SBC aftermarket ones, it's quite likely, but new from VW??? I dunno. I suppose it's also possible a mouse crawled up into the block somewhere when it was open for draining. I did leave it overnight the hoses open disconnected. It was on a lift though, but mice are known to perform acrobatic moves snd they like sweet coolant, but this G13 stuff is organic based it's not sweet like green prestone.

After reviewing historical weather data, I don't think this problem existed prior to me buying the car and it working fine in the cold months when I first got it. I know I drove it down to my cutsomer 200mi away on June 8th and weather says it was 68-82 that day or around 77 while I was driving, so no way it would have made it 200mi in that ambient temp and it was not having an issue on the way down there, no problems at all, until my return trip on the 12th when the temp was around the same in the mid to low 70's. 

I dunno, perhaps it's wishful thinking ... but the ability to have the behavior change with t-stat and sensors followed by no water flow where there was some...i'm kinda thinking I got a bum t-stat?


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## 73blazer (Feb 19, 2020)

According to the schematic of the cooling system, the rear sender (5) is right in the main output pipe which runs through pipe (29) goes to a tee which feeds both radiators. And both radiators return to the tstat housing.










I mean, in the grand mess of stuff in that cooling system, the main loop is fairly contained and simple. So there's either blockage in that pipe from the rear of the motor to the radiators or the tstat isn't opening or the main water pump isn't moving. I don't think there's blockage in the motor itself, because if the afterun pump runs which bypasses the t-stat (it goes to the t-stat housing but to that other inlet which routes right to the back not through the main t-stat in there), the motor temp drops. If you turn the heater on, which bypasses the tstat, the motor temp drops. So the motor is capable of being cooled. I think main water pump is safe to declare ok. The main radiator isn't getting hot water so it's not the radiator, besides there's two. It kinda has to be that t-stat not letting water pass.


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## Phaetonlvr (Feb 26, 2013)

I would agree with your assessment that the t-stat is most likely not working/staying closed. As you can see from my drive cycle the radiator isn't really used that much with the current ambient temps so that would explain why it takes a while for your temps to get excessive and the fact that the heater cores and after-run can sufficiently cool it is another indicator. A blockage is a possibility but for something large enough to get in there it really would have to be something like a mouse crawling in there while it was open.

I'm assuming that the t-stat duty cycle data is the commanded value not the actual feedback from the t-stat. Did you do the electrical check at the connector as listed in the original t-stat replacement thread by Michael Moore? I remember there was a test to be carried out to ensure the VW warranty paid for a new t-stat.


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## 73blazer (Feb 19, 2020)

I did not do that test. 
However, it is supposed to mechanically open at 210 or 215 or something as a safety backup and it goes way beyond that. So....i dunno.

Here's the 64,000$ question, if a mouse crawled up into that main pipe from the back of the engine to the radiators, wouldn't it boil away eventually at least the main body. I mean people boil deer and caribou and moose skulls to get all the organic material off the bones, and if your not careful you can boil away the bones if you leave it too long. My point is, I would surmise that condition would slightly get better after a few hot drives, or enough water would pass eventually to not cause a problem at these ambient temperatures.


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## 73blazer (Feb 19, 2020)

53PL-50AAA-VW611BAN said:


> Does it get that hot at home or only when you are driving? - *BOTH*
> 
> Do you let it warm up at home? Have you tried idling it at home until it heats up? - *Yes, it will overheat*
> 
> ...


Answers in bold


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

73blazer said:


> 53PL-50AAA-VW611BAN said:
> 
> 
> > You can point the IR thermometer at both ends of the hoses to see if a hose has different temperatures on each end. - *I might try that but if no water is moving thru one end will be hot the other cold*
> ...


Exactly. One end will be hot and the other end will be cold if there is no flow. If a hose is cool when it's supposed to be hot, that's probably also an indication of no flow.

I'd suspect air in the system but It's possible the thermostat is bad. Can you point the IR Thermometer down on the Thermostat output hose?


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## dlouie (Oct 31, 2008)

Simple and perhaps effective.
This guy just spliced clear polyurethane tubing into the radiator hose to visually see flow.
https://youtu.be/EjvkoYvQ06E


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## Phaetonlvr (Feb 26, 2013)

Not sure what to suggest next, I guess verifying the t-stat responds to commands and the main tubing/hose going to the radiator has flow. The clear tubing is a nice trick but probably difficult to do on the radiator end with the proprietary fitting which makes it impossible to connect to.

Btw, did that Dayco serpentine belt work out ok, is it a good fit? Might snap up a couple at RockAuto for that low price.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

Phaetonlvr said:


> Not sure what to suggest next, I guess verifying the t-stat responds to commands and the main tubing/hose going to the radiator has flow. The clear tubing is a nice trick but probably difficult to do on the radiator end with the proprietary fitting which makes it impossible to connect to.
> 
> Btw, did that Dayco serpentine belt work out ok, is it a good fit? Might snap up a couple at RockAuto for that low price.


Not to mention that the W12 has a zillion hoses. Which expensive hose do you cut up to see if it has coolant flow?

I'm also curious about the Dayco belt.


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## 73blazer (Feb 19, 2020)

The Dayco belt seems to fit perfectly. I compared it's effective length to the OEM, same (I don't remember the number now some mm I think worked out to 101.4").
It was slightly shorter than the one I took off but that's attributed to those things will stretch some for sure. The tensioner needed moved all the way to get the belt on and only came back slightly so the tensioner has pretty much full range to move back still. And, it's quieter than the old one, which I've no idea what brand it is as being dual sided ribbed there's no name or numbers on it. The dayco belt seems to be some poly fibre/rubber mixture, they actually tout it will be quieter and more durable than most oem belts. WHo knows, but it fits, it is quieter (by quieter I mean, you can't really hear the old one with the hood closed but I've spent soo much time with the engine running and hood up I noticed it was quieter.


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## 73blazer (Feb 19, 2020)

I was able to get to the t-stat connector on the back of the block, disconnect it and there was just enough to get the t-stat lead up above where I can jump it. I'm gonna try warming it up and forcibly just 100% open by putting 12v to that t-stat lead. 
I did measure it's resistance, it's 15-16ohms right where it's supposed to be. 

And..... it warms right up and keeps going. I plugged the t-stat to 12v constant and left it and it warmed up in the same amount of time it normally does, and keeps going up. I was able to get the IR gun on the main pipe under the right cylinder bank it's consistently hot, 230-240ish at the back of the block, 220-230ish at the front tee, and rad input tank on the right side is 190-200ish. 
With a wide open t-stat it shouldn't warm up at least not quickly, I mean that thermo-resistor in there isn't gonna open when the block is cold not sitting in cold water aka it's not gonna heat all that water enough to warm it enough to open..., but it certainly shouldn't warm up nearly as quickly. And once at temp it should basically just be wide open. 
I did get the code tthat says open map controlled t-stat circuit, so, the computer saw I had it disconnected which was expected. 

I was also able to verify the plug coming from the computer that operates the t-stat had a voltage commensurate with the duty cycle, aka 10.5v for 80%, 8v for 60%...etc. I don't remember the numbers exactly but it went up and down with the duty cycle displayed in VCDS. 85% which is the max the computer will go was like 11.2v or something IIRC. 

I dunno, it seems the t-stat is....not opening to me.


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## dlouie (Oct 31, 2008)

I think at this point you need to verify flow through the radiator alone. If everything seems good on the control end, a block radiator or poor flow through it effectively could look like a blocked thermostat. The reverse is true. The testing you've done can suggest a blocked radiator as forcing the t stat open on warm up yields no change in warmup times because there's no flow through the radiator, just like a closed t stat. Do I make sense?


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## 73blazer (Feb 19, 2020)

You make sense. However i was able to jamb the hose in the upper and watch it flow freely.out the lower when the lock carrier was in service position. That and the afterrun pump seems to have no issue flowing through there which i can verify with the ir gun the input side tank temp stays same and output side goes up from where it was while engine running indicating flow is happening. I believe the radiator is flowing. It wouldn't need to flow much to keep temp and the aux rad would need plugged up too. Seems unlikely.


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## Phaetonlvr (Feb 26, 2013)

Thanks for the info on the Dayco belt, for $5 each I'll get me a couple spares.


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## 73blazer (Feb 19, 2020)

At this point I'm half ready to.just remove he tstat and remove the plates from.it and reinstall.it. In the interest of diagnotics. I'm not sure I could take installing another thermostat and having the same problem. I'm guaranteeing myself two intake dis assemblies butt. If I did a thermostat again and I had the same problem.... I might be tempted to drive this car into the Lake.


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## 73blazer (Feb 19, 2020)

I really want to Thank everybody for the help here it's been a frustrating problem . The thoughts and ideas expressed by everybody in this thread have really helped me to try and diagnose this problem. I hope i can get to the bottom of it. Especially like to thank Stephan for the same data parameters logging that I see. So I know what a normal W 12 is supposed to act and look like. I don't give up easily. I think I've shown that hopefully. But it is a really frustrating problem. Even if I junked his car. Id take this motor apart to see what the hell was blocking The water cooling. Without this forum specially the Members that belong to this forum and contribute to.it... The pointers to the self study guides. The little ideas...I would be completely lost.so. Thank you! I can only hope I can contribute as much to this Forum in the future as you all have contributed to this thread.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

I think you tested the old thermostat in hot water in post #47. 

Did you test the new thermostat in hot water before installing it?


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## 73blazer (Feb 19, 2020)

I would think a $300 t-stat would be tested for you, with a free ticket for a night with a celebrity of your choice complete with happy ending. 
No, I did not test it. I was to afraid of "damaging" it.


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## Phaetonlvr (Feb 26, 2013)

We are all happy to help but this is one perplexing problem and frustrating to us commenters as well. I sure hope you can get to the bottom of it eventually.

I looked at the trends again and even though on my car I started with a cold engine and just got to operating temperature at the end of the trend, it looks like on my W12 I get a larger temp delta when the t-stat opens. Of course that could be because most of my driving was at freeway speed which provides significantly more air flow than the fans on a stationary car. Could it be that the radiator is partially plugged? You are getting some flow through it but maybe not enough to achieve the required cooling? Other than that it probably still points to the t-stat.


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## 73blazer (Feb 19, 2020)

In a couple days I'm gonna leave for deer hunting with my dad and brothers and uncle. I have time to take apart either the front end for radiator or top end for tstat . Your vote counts. I have 1 vote and i vote top for tstat. What say you? I vote the way i did because i did run a hose test on the rad while doing the water pump and it seemed ...seemed to flow ok. . It's not a perfect test i know. But at this point i have to do one or the other. Rad apart loxk carrier back way out front lets me snake the line from bottom.of rad to back of block so there's advantage to that.. I not using the car to go hunting the goal.being rule out one or the other while I'm.gone son i can order parts and have it back together by the end of November


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## dlouie (Oct 31, 2008)

I vote radiator! Use a thermal camera and watch everything from cold.


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## 73blazer (Feb 19, 2020)

dlouie said:


> I vote radiator! Use a thermal camera and watch everything from cold.


Well, I don't have a thermal camera. But even if I did, what to look for, as I think no flow from lack of t-stat letting it open, versus no flow through radiator might look the same. indeed I can take the IR gun and get 175-190ish F on the input side and the output side is 65-80. When the afterrun pump runs output side gets closer to 110-120 F (the fan only runs very low speed during afterun) indicating to me something flows through there then.


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## 73blazer (Feb 19, 2020)

Well, i did the t-stat. Boiled it. It opens, quicker if the batt is connected to the leads, but it'll open on it's own if you let the water get to 212F. 

But what's this bottom plate do on the t-stat????. It does not move. In the bottom of the t-stat cavity in the block there is two holes one leads to the water pump, the other gets sealed up by this bottom plate. If this plate doesn't move I don't see how anything could move through there, and it seems since it's there something should flow thru there???
I can depress itt with my fingers, it takes quite some effort though. The old one is the same on that plate. 

What hole is that plate sealing and is it supposed to move?

dlouie might have been right???!?!?!?

The good news is since I just did all this I was able to take all this apart in a matter of minutes. I'm sure I could the front end in minutes as well.


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## dlouie (Oct 31, 2008)

Check SSP222! It fully explains how it works! Fascinating. 

http://www.volkspage.net/technik/ssp/ssp/SSP_222.pdf

There are two cooling circuits, a small and large. The end of the thermostat is known as the small disk and is the control for the small cooling circuit. It is linked mechanically to the another disk that controls flow to the large cooling circuit. When the large opens, the small closes but with the electric control of the t-stat, both can be varied to a degree. Even without electrical control by the computers, the t-stat can still regulate coolant flow passively,


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## 73blazer (Feb 19, 2020)

Well, even more preplexing...after watching it open while boiling...

I said F-it, I'm not putting this back together without 100% knowing something isn't going on with that t-stat i don't care if I have to buy another or take it apart again.I removed the bottom plate and cut two notches in the main upper plate so even if the thing won't open in the engine...it should have about 1/3 flow. ANd put it back together. 
And....while I didn't drive it (it's clean and was pouring rain and I live on a dirt road...and it's 2am), I let it idle for a while in the garage..took way longer to warm up ... and the pattern looks alot closer to Stephans now once it did warm???????

We'll see when I drive it tomorrow. I'm not quite convinced.


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## dlouie (Oct 31, 2008)

I was looking at the cooling routing. The upper hose has an integrated non return valve. Could it be that the valve is restricted? Check it if you haven't.


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## Phaetonlvr (Feb 26, 2013)

Thanks for the link to that SSP, Damon. I hadn't read that one before and it sure is interesting to see how the system works.

There is indeed a check-valve in the upper radiator hose, it's part of the elbow on the radiator side of the hose. It should move freely when empty, you can actually hear it move if you have the hose off and move it around.


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## dlouie (Oct 31, 2008)

SSP921403 is a good read too!

https://silo.tips/download/60l-w12-engine-in-the-audi-a8l-self-study-program-course-number


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## Phaetonlvr (Feb 26, 2013)

I've read the Phaeton W12 SSP before but this looks like a good one also. I know what I'll be doing tonight


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## 73blazer (Feb 19, 2020)

Here's a 60mi drive today. Mostly 80mph cruise control. Alot closer to stephans profile. The stat-modification consists of removing the bottom plate and two notches in the main plate about 1/3flow. It did take alot longer to get up to temp. So now I have rad output following t-stat duty cycle like stephans. 

Held all the way. *Until *I let it idle back in the garage at home, then...it goes up. So, what's up with that. Clearly the t-stat modification helps it. But still overheats idling?
Did I have a bum new t-stat on top of a bad radiator?????? POssibly blockage somewhere else. :banghead::banghead::banghead:

I'm unsure what to make of this data.


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## dlouie (Oct 31, 2008)

"If both senders fail, maximum voltage is applied to the heating resistor and the 2nd fan speed stays activated."

Per the SSP. That means the failsafe is that the thermostat is full open and would seem that the large cooling circuit is completely open and the small is closed off. Did you try disconnecting both sensors and log that data. If at this point there is insufficient cooling even at idle with both fans on, I think there is a blockage somewhere from after the t-stat outlet all the way to the waterpump. I'm talking out loud here.

Additional notes:

"Substitute function If coolant temperature sender G62 fails, a defined substitute value of 95oC is used for coolant temperature control and the 1st fan speed stays activated. If coolant temperature sender G83 fails, the control function remains active and the 1st fan speed stays activated. If a certain temperature threshold is exceeded, the 2nd fan speed is activated.


Check that non return valve in the upper radiator hose.


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## 73blazer (Feb 19, 2020)

Well I've not tried disconnecting sensors but i did try removing the tstat connector and forcing it to 12v constant. It didn't help. Overheated while idling. I also did have that upper hose removed when i originally did the first tstat and the check valve was free and moving. You could shake it back and forth and clearly hear it moving in there.

It seems crazy the data makes no sense. This car should be able to run death valley at 150mph with the a/c on and not overheat. There should be so much reserve cooling capacity at idle at 45f ambient it should never overheat without fans and with a 90% blocked up radiator...and if it does the problem should be blatantly obvious where the problem lies. Very perplexing.


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## dlouie (Oct 31, 2008)

This is what I'm thinking with the thermal camera. I have one that's plugged into my phone. It's a Flir One.

https://youtu.be/KqOodFvHYDM


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## Phaetonlvr (Feb 26, 2013)

73blazer said:


>


Indeed perplexing! 

Here's what I see when looking at the time period when the hot engine was idling which looks to be around timestamp 5016. The thermostat keeps opening more and more following the increasing engine output & oil temps as expected. The radiator output temp also rises except when the coolant fans increase speed at which point the radiator output temp responds very quickly, also as expected. What is interesting is that the specified engine output temp and the actual output temp are deviating further apart the longer it idles but oil & engine out temps track parallel so the engine is actually overheating (which we knew already) but the ECU thinks it shouldn't based on engine load, rpm and road speed. Either there is a reason why there is additional unexpected heat getting generated (unlikely I think because even if that is the case the thermostat would open more) or the heat transfer is somehow limited. The later could be that maybe the oil/coolant heat exchanger is not cooling the oil down making the block hotter!? Maybe some coolant flow is bypassing the radiator in some way and feeding the engine with hotter coolant (that would have to be downstream of the radiator outlet temp sender)?

Could it be that there is a partial restriction somewhere in the main cooling loop that only shows up at idle. Maybe at higher engine rpms the water pump can overcome that restriction but not at idle speed? The water pump is a centrifugal and not a positive displacement pump so that limits how much backpressure it can overcome on the discharge side.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

Is the electric water pump working?


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## 73blazer (Feb 19, 2020)

Which one! There's three. Two for the heater and one for the after run and idle assist. I've checked the afterun pump. In an earlier post in this thread i detailed taking the floor apart on the passenger side removing the relay and jumping the pump on. In that state with the car off and no fans running you can clearly hear it i out my hand on it it's buzzing and feels running.checked the relay its fine. Checked for relay power when the car was warm and saw power to the relay ap the ecu is doing its job. And the rad is dumping heat during normal afterun and if i restart the car after just 30s or so it drops temp big time. so clearly its moving water . Another reason i doubt radiator itself. It seems working. 

I actually bought a new one of those as their fairly.cheap but i find no procedure in the book on how to replace it and i see no easy way to access it and remove it without removing the engine. Plus mine seems.to function. Plis you shouldnt need it to idle at 45f i known it says idle assist but i think that would be for very hot days. That sucker is buried in there.


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## dlouie (Oct 31, 2008)

I don't think the after run pump is in the large cooling ciruit. I think it's part of the small circuit which is the oil and atf coolers so that is where you are shedding heat when off. So don't rule out the radiator. By modifying the t-stat, it might look like you are achieving suffient cooling but that could be because you have additional cooling from the small circuit that would normally be closed when the t-stat is fully open.


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## 73blazer (Feb 19, 2020)

The afterrun is in it's own circuit all together according to the diagram and from my observation. it pulls from that tee in the upper radiator hose and dumps back into the top of the t-stat housing but on that separate arm which bypasses the actual t-stat.

As unlikely as it seems, It has to have some blockage somewhere. It IS possible, I guess, the motor itself it blcoked but as I've stated earlier the heater core seems to pull down the temp but after thinking more about that, it could just be dumping back near the engine out coolant I'm not sure how all that physically is connected back there but it's possible the heater loops is dumping back near the engine out sensor and just fooling the car into thinking the motor is cooler when it really isn't.
The main loop is pretty simple outside og the block, leaves block in rear through hard pipe under right cylinder head into tee through both radiators and back to the t-stat housing on top/front of motor. so.


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## dlouie (Oct 31, 2008)

Pump V51 is part of the large cooling circuit. Interesting that the Audis are not according to their diagrams.


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## 73blazer (Feb 19, 2020)

dlouie said:


> Pump V51 is part of the large cooling circuit. Interesting that the Audis are not according to their diagrams.


Diagram I posted above from the 2005 phaeton service manual shows it it's own circuit. I know it tees off the main upper hose at that check valve not sure where the other side goes in but the diagram shows it at the t-stat housing bypassing the actual t-stat in the housing. So it'll pulling out of the radiator and dumping in to the engine block


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## Phaetonlvr (Feb 26, 2013)

Here's a somewhat accurate diagram of the cooling system in the BAP W12. This is the main cooling circuit https://www.jimellisvwparts.com/showAssembly.aspx?ukey_assembly=741875&ukey_make=1066&ukey_model=15568&modelYear=2005&ukey_category=21729&ukey_trimLevel=18932

This is the diagram for the coolant line towards the heater core and aux pump. https://www.jimellisvwparts.com/showAssembly.aspx?ukey_assembly=740788&ukey_make=1066&ukey_model=15568&modelYear=2005&ukey_category=21729&ukey_trimLevel=18932

I suspect both aux pumps are on the LH side in front of the front wheel. I had to replace hose #19 in the second diagram due to a broken off nipple and can confirm the routing on that diagram. The other aux pump is shown on the first diagram and it takes the coolant from the radiator at the bottom left and dumps it into the upper radiator hose downstream of that check valve.


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## 73blazer (Feb 19, 2020)

Still waiting for my 3rd radiator to show up, hopefully is usable condition.
I did take the car on a 1000mi trip, 500mi one way, stayed there about a week driving around a few times to get groceries and...winter tires...and 500mi back, no problems with overheating, but it was max 32f out, most of the time in the lower 20's or lower and some heavy snow (Car is a dream in snow and ice with winter tires, and in that area they don't salt alot, because they get so much snow, mostly only salt the intersections...what few of them there are, and sand the hard pak snow roads after plowing). I hope I can get this fixed, as driving it on long road trips is awesome and what I really bought it for! Not supposed to be a garage queen, I want to drive it!

There is one interesting thing, the oil temp seems...to fluctuate, even at cruise for 100mi at 65mph. Never got above 200f, sometimes it's 160, and slowley creeps to 200 and back down to 180, mostly stayed around 180ish..this is mostly flat ground some very small climbs . I know it has the coolant heat exchange oil cooler, so is that some sort of indication of some issue with that? Shouldn't affect the main loop, but it does seem curious to me why it's moving around with mostly constant temps and engine load. This is all at below 32F temps. I've also noticed during the overheating conditions when it's above 50-60F that the oil moves up to 200, stays for a while like 10-20mi, then starts moving upward and then that's when the coolant temp starts going above 200F too. As in, say it's 70F ambient outside, coolant gets to 200F fairly quickly, stays there, oil takes a while like 15-20mins more to get there, then it stays, for a while another 10-20mi, then they both start going up oil first but coolant quickly (within 1-2mins) following. Can anything be discerned from that observation?


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## Phaetonlvr (Feb 26, 2013)

My radiator arrived at 1stvwparts on Friday and they shipped it right out to me, should be here on Tuesday. Can't wait to see if it survived the trip.

Not sure what to make of the fluctuation in oil temperature. On mine it takes usually around 20 minutes for it to get up to 200F, lagging way behind the coolant temperature as it should, even on hot days. I've never looked at if or how the system controls the coolant flow to the oil heat exchanger that is part of the oil filter housing. But even if it controls that, the actual oil temp sensor is at the bottom of the oil pan on the LH side so an oil temp change would have to actually change all of the oil in the pan and that would take a while.

Btw, my silver W12 started throwing a Cooling System Fault the other day. AFAIK it's the one that gets logged when the cooling temp is outside of what the calculated temperature should be, apparently usually when the engine is running too cool. I have to finish logging a few comparison drives with my other W12s but seems like my thermostat is staying open at all times. I'll post up my own thread for this problem in a few days.


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## 73blazer (Feb 19, 2020)

Phaetonlvr said:


> My radiator arrived at 1stvwparts on Friday and they shipped it right out to me, should be here on Tuesday. Can't wait to see if it survived the trip.
> 
> Not sure what to make of the fluctuation in oil temperature. On mine it takes usually around 20 minutes for it to get up to 200F, lagging way behind the coolant temperature as it should, even on hot days. I've never looked at if or how the system controls the coolant flow to the oil heat exchanger that is part of the oil filter housing. But even if it controls that, the actual oil temp sensor is at the bottom of the oil pan on the LH side so an oil temp change would have to actually change all of the oil in the pan and that would take a while.
> 
> Btw, my silver W12 started throwing a Cooling System Fault the other day. AFAIK it's the one that gets logged when the cooling temp is outside of what the calculated temperature should be, apparently usually when the engine is running too cool. I have to finish logging a few comparison drives with my other W12s but seems like my thermostat is staying open at all times. I'll post up my own thread for this problem in a few days.


I can swap a t-stat on these in an hour now. Simple job! The $300+ for the t-stat isn't so fun though. Be gentle with that front hose coupling when you pry it off the t-stat housing, lest you might break the small nipple on it like I did!


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

73blazer said:


> I can swap a t-stat on these in an hour now. Simple job! The $300+ for the t-stat isn't so fun though. Be gentle with that front hose coupling when you pry it off the t-stat housing, lest you might break the small nipple on it like I did!


Doesn't it have a quick release clip?


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## 73blazer (Feb 19, 2020)

53PL-50AAA-VW611BAN said:


> Doesn't it have a quick release clip?


It does, but it wants to kinda stick on there after you pull the clip up (kinda like stuff like..water pumps will stick to the block after you've removed the bolts, until you give it a little love tap), and if your prying motion involves too much force, it will move back too much or too quickly, and break the small nipple (BAP cars only) because that small hose cannot move more than a a few mils.


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## Phaetonlvr (Feb 26, 2013)

73blazer said:


> I can swap a t-stat on these in an hour now. Simple job! The $300+ for the t-stat isn't so fun though. Be gentle with that front hose coupling when you pry it off the t-stat housing, lest you might break the small nipple on it like I did!


I haven't done the t-stat on a W12 yet, two of mine had it already replaced by the time I got them. I've done the spark plugs and valve cover gaskets before and had the intake manifold off but haven't taken the lower intake manifold off. Not worried about it, just need to get all the parts together.


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## Phaetonlvr (Feb 26, 2013)

73blazer said:


> Still waiting for my 3rd radiator to show up, hopefully is usable condition.


Received my radiator today. Looks like 1stvwparts did a decent job of putting extra packaging material inside the box but unfortunately not enough for such a heavy part. Surprisingly none of the coolant hose connections, especially that small one on the corner, got damaged but one of the mounting pins penetrated the box during shipping and got knocked right off. So the radiator itself is probably fully functional but having a missing mounting pin, especially the one next to the large coolant hose connection, would be a problem as it would constantly pull and push that corner of the radiator around.

I just emailed them to get a replacement ... fortunately this is just a spare for me so I'm not in a hurry. Can't believe we now lost a total of 3 radiators to bad shipping/packaging practices, what a waste!!


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## 73blazer (Feb 19, 2020)

Phaetonlvr said:


> I haven't done the t-stat on a W12 yet, two of mine had it already replaced by the time I got them. I've done the spark plugs and valve cover gaskets before and had the intake manifold off but haven't taken the lower intake manifold off. Not worried about it, just need to get all the parts together.


The hardest part is that lower intake, I've had to remove a bolt or two from the fuel rail in order to get just a couple more mm of clearance (make sure you car has been sitting a while.... if the rail is still pressurized you might get a spurt or two of fuel as you gently nudge the rail aside as the intake is coming out), remove all the inside injector clips from botth sides and bend the tabs on them on one side to get the lower intake off. The bending tabs isn't so fun as they will eventually break if you do that job on one car enough times. Mine already had one -tstat done, I did one, then did the modified one, and there's one more to put another new one it after I've determined the cooling issue is solved.

Yeah, I think those radiators are loose in the box from the supplier and every one is gonna get junked by the time it gets across the pond. Mabey your silla radiator is the way go i have little confidence any one of those OEM ones from Germany are going to arrive in tact.

BTW, do you know where the procedure in the book is to replace the aux cool down pump? I find the ones for the heating pumps in front of the drivers wheel but I don't find anything on how to do the aux cool down pump. WHile I've jumped the relay in the passenger footwell and felt my pump at least vibrating, I'd like to replace it if I can, I have a new one. It's not obvious how it comes out and itt does not look fun to get at, i'd like to see how the book wants you to do it but I don't find a procedure in there for it.


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## Phaetonlvr (Feb 26, 2013)

73blazer said:


> The hardest part is that lower intake, I've had to remove a bolt or two from the fuel rail in order to get just a couple more mm of clearance (make sure you car has been sitting a while.... if the rail is still pressurized you might get a spurt or two of fuel as you gently nudge the rail aside as the intake is coming out), remove all the inside injector clips from botth sides and bend the tabs on them on one side to get the lower intake off. The bending tabs isn't so fun as they will eventually break if you do that job on one car enough times. Mine already had one -tstat done, I did one, then did the modified one, and there's one more to put another new one it after I've determined the cooling issue is solved.


Thanks for the heads up on that. I remember reading the original t-stat thread before and it also mentioned the tight clearances around the fuel rail tabs. I'm contemplating to just take the fuel rail off and replacing all the injector o-rings while I have everything apart. I'm also dealing with a recurring "Mixture Regulation - Rich Limit Exceeded" fault that was temporarily solved with a new fuel pump last year but keeps coming back. Might send out the injectors for a cleaning to see if that causes the rich condition.




73blazer said:


> Yeah, I think those radiators are loose in the box from the supplier and every one is gonna get junked by the time it gets across the pond. Mabey your silla radiator is the way go i have little confidence any one of those OEM ones from Germany are going to arrive in tact.


Agreed, the box is the original one from the OE supplier (has the original part # sticker, Made in GB) and there seems there never was any provisions to keep that radiator secured inside the box. 1stvwparts did put some bubblewrap into the box before they forwarded it but it really needed additional layers of cardboard around both end tanks to protect it. Anyway, the next one is on the way.



73blazer said:


> BTW, do you know where the procedure in the book is to replace the aux cool down pump? I find the ones for the heating pumps in front of the drivers wheel but I don't find anything on how to do the aux cool down pump. WHile I've jumped the relay in the passenger footwell and felt my pump at least vibrating, I'd like to replace it if I can, I have a new one. It's not obvious how it comes out and itt does not look fun to get at, i'd like to see how the book wants you to do it but I don't find a procedure in there for it.


There's the "V36 coolant pump" which is in front of the LH front wheel and pump from LH lower radiator outlet to the upper radiator hose downstream of the check valve. The other one according to the manual is "V55 circulation pump" but I don't know where it is physically located on the W12, it's only shown on the coolant flow diagram and not mentioned anywhere else in the manual. I haven't dealt with these pumps on my W12s so can't help on the procedure. The V8 also has two and I think one was on the LH front and the other on the RH side of the engine at the bottom.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

The .pdf version of the manual has a V55 Circulation Pump but doesn't show a picture.


The physical W12 Study Guide shows the V51 Coolant pump on page 51, but it's on page 49 of the online version:



http://www.volkspage.net/technik/ssp/ssp/SSP_250.pdf



I didn't see a V55 in either study guide but I didn't check every page of the physical copy.

The Bentley shows a V51 picture but shows the V55 in the coolant hose schematic.

The wiring diagram shows a V51 but no V55 or V36. Maybe I missed the V36 but I read through the wiring diagrams twice and even read the 2005 and 2006 diagrams and the V8 engine wiring diagram. Curiously, the V8 wiring diagram also shows a V51 but the link goes to the 6.0 picture.

I hope you can open the .pdf files.


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## 73blazer (Feb 19, 2020)

Well, I know where it is, I can see it. It's mounted to the drivers engine mount. I can get my hand on it and I felt and heard it buzzing when I jumped the relay to it under the passenger floor, but do not see any obvious way it can come out. Even if you could disconnect the two hoses from it, which could probably be done with some frustration, and you _might_ be able to get the two mounting bolts off, but I see no way that thing is gonna come out without raising the engine somewhat or removing the engine mount, if that's possible on the car.


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## Phaetonlvr (Feb 26, 2013)

That sounds like a tight area. I haven't had to deal with this pump yet so can't give you any hints. If it's buzzing when you jump it then I'd be pretty sure it's working. Those little pumps are pretty simple if they are similar to what's in the V8s. Can you remove a hose on the discharge side of the pump and see if you can get flow when you jump it?


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

I agree with Stephan, it sounds like it's working. 

If you decide to remove it, perhaps it will come out from underneath or if you move the left fender liner out of the way. 

The fender liners seem to be pretty flexible. 

I can't remember what they were doing, but once on 7579 the mechanic had the right fender liner bent back out of the way to gain access for something. He just removed the front screws and bent it over on itself. While it was open, I checked to make sure that lug on the cover was removed.


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## Phaetonlvr (Feb 26, 2013)

It's so easy to take the fender line off, that I do that even for the oil change on the W12. Of course it's easy for me because I have a lift so taking a wheel off to get to the fender liner. But even having to jack up the car to take the wheel off is still worth all the access you gain.


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## Phaetonlvr (Feb 26, 2013)

Well, looks like I'm dealing with a bad thermostat on one of my W12s now. I started my own thread at Another W12 Thermostat Failure? Fault Codes 18613 &amp... so as not to hijack this one.


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## Phaetonlvr (Feb 26, 2013)

73blazer said:


> That center plate 07C-103-185-B behind that t-stat I told you guys about that was leaking as well every so slightly under the pressure test (and looked like it had been leaking for some time after witnessing where exactly it was leaking). The new plate is a D part and has reinforcing ribs on it. Apparently, it warps. It should spec longer bolts, but it doesn't, but I think there is still plenty of thread engagement.


I just ordered one of those Suffix D plates since I have to replace the thermostat. There's no gasket shown in ETKA for this part but I assume it comes with a new one? Can you confirm that please.

Btw, the second new W12 radiator is still on the way over from Germany, let's hope this one survives undamaged but I have my doubts.


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## 73blazer (Feb 19, 2020)

Phaetonlvr said:


> I just ordered one of those Suffix D plates since I have to replace the thermostat. There's no gasket shown in ETKA for this part but I assume it comes with a new one? Can you confirm that please.
> 
> Btw, the second new W12 radiator is still on the way over from Germany, let's hope this one survives undamaged but I have my doubts.


Yeah the plate comes with a gasket.
My dealer got another rad from germany, busted to pieces. 2 left. Another one on it's way!

BTW, a guy from TX called me from my k5obsolete.com website and wanted a fitting that I printed. His was leaking exactly where mine was, top part of the fitting rotted thru. SInce he really needed one I sold him one. I think mines been on there long enough and in cold and heat to say it's ok. My car works great in MI winter, no overheating (it also still has my modified t-stat) i've been driving it quite a bit I even fitted winter tires on it, that car's a beast in the snow with winter tires. . 
So, if someone wants one I can sell it. I'll have a checkout on my website within a week or so.


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## Phaetonlvr (Feb 26, 2013)

73blazer said:


> Yeah the plate comes with a gasket.
> My dealer got another rad from germany, busted to pieces. 2 left. Another one on it's way!


Thanks for confirming that, my parts for the thermostat project are scheduled to arrive today.
The second radiator from Germany is still on it's way but the first one, that had one of it's mounting pins busted off, is still here, they still haven't asked for it to be returned so looks like I might end up with it. I think I can make that one work by either epoxying the pin back on (it's the one on the LH top where the large outlet hose goes) or fashioning some kind of retaining bracket.



73blazer said:


> BTW, a guy from TX called me from my k5obsolete.com website and wanted a fitting that I printed. His was leaking exactly where mine was, top part of the fitting rotted thru. SInce he really needed one I sold him one. I think mines been on there long enough and in cold and heat to say it's ok. My car works great in MI winter, no overheating (it also still has my modified t-stat) i've been driving it quite a bit I even fitted winter tires on it, that car's a beast in the snow with winter tires. .
> So, if someone wants one I can sell it. I'll have a checkout on my website within a week or so.


Sounds good, keep us posted when the link is available.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

73blazer said:


> BTW, a guy from TX called me from my k5obsolete.com website and wanted a fitting that I printed. His was leaking exactly where mine was, top part of the fitting rotted thru. SInce he really needed one I sold him one. ~
> 
> ~ So, if someone wants one I can sell it. I'll have a checkout on my website within a week or so.


I'd want one too.


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## 73blazer (Feb 19, 2020)

The dealer called yesterday and said they got another radiator in. Thankfully, it was undamaged! 3rd times a charm I guess.


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## Phaetonlvr (Feb 26, 2013)

That's good news. Still waiting for my second one to come in.


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## Shyheim103 (Aug 27, 2017)

It took a while for me to get my radiator too. In fact, Rockauto banned me from buying anymore, lol. I think i got a good one my third time as well.


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## 73blazer (Feb 19, 2020)

Somebody got the message with the returns, this had cardboard over the core area, was double boxed and with plenty of packing between boxes and in the inside box to ensure the nipples couldn't receive any weight or impacts.


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## Shyheim103 (Aug 27, 2017)

73blazer said:


> Somebody got the message with the returns, this had cardboard over the core area, was double boxed and with plenty of packing between boxes and in the inside box to ensure the nipples couldn't receive any weight or impacts.


Ha Ha! Mine was like that too on the third time! Be careful of that little tube on the top passenger side. That was broken on my first one.


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## Phaetonlvr (Feb 26, 2013)

That makes me hopeful that the second one will get here undamaged.


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## Phaetonlvr (Feb 26, 2013)

My radiator finally arrived and it did in fact survive undamaged. It had no special protection inside the box from the manufacturer but Auburn VW (1stvwparts) did an excellent job in re-boxing it with extra protection. I'm still a little surprised that the manufacturing tolerances as the whole core is ever so slightly bent and the core is too solid of a piece for that to have happened during shipping as there are no marks that would have caused that. Anyway, I'm sure that's not going to be an issues as the rubber mounts will take up any slight twist in the assembly.


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## 73blazer (Feb 19, 2020)

Well I finally decided to tackle this.
I've had the new radiator, and another 2 new sensors, and another new t-tstat, and even bought a new upper C-hose just for the diverter valve thing in there, I removed the front facia again tonight, disconnected the upper and lower hoses let it drain and moved the carrier out a bit getting ready to remove the radiator.
Anyway, after it's done dripping a bit all over the cement I drag the garden hose in and spray down the whole area under it and all over the engine/fan/rad parts that coolant dripped on so the next day I have a nice clean dry non-sticky/wet area to work on. While spraying with the garden hose, for fun, I took it and blew it into the upper radiator nipple. To my surprise it blew my hand back off the nipple with blowback water and only a trickle of water was coming out the lower nipple. I did that a couple times.

So I _may_ have a glimmer of hope  that it is actually the radiator. It would make total sense as the car acts as if it just doesn't have coolant flow. and it's literally the only part of the main circuit I haven't touched. I could have sworn I did that last time the rad was in service position doing the water pump but who knows I've taking that thing apart so many times I can't remember what I did and didn't do, seems I would have done it.


Pray..hope...it's the raditor!!!🤞🤞🤞🤞🤞🤞🤞🤞
Now I just need to figure out how to get the radiator out of the carrier. (I have the manual..just trying to discern it).


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## Phaetonlvr (Feb 26, 2013)

Taking the radiator out is pretty easy, You remove the whole radiator fan structure (including the fans) which I believe is just 4 screws and then you remove the screws holding the top and bottom radiator rubber supports to the structure. The AC Condenser is mounted to the front of the radiator with four screws so if you did not disconnect the refrigerant lines from the condenser then you'll need to remove those screws first to keep the condenser in place when you remove the radiator rearwards.

Let' hope the problem is indeed the radiator!


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## Shyheim103 (Aug 27, 2017)

Yeah, the radiator isn't bad at all to remove. That whole carrier is heavy though! Hope that's the problem.


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## 73blazer (Feb 19, 2020)

I got it out. I did have to remove the hood latch though, it's bracket sticks down behind the fans/rad and prevents you from leaning it backwards to pull it out.

I ran the garden hose through it again off the car standing on end to give it the fullest advantage, and it will fill up that side tank and blow back before it runs out the other side, when you stop flowing water through it it makes a gurgling sucking drain noise as the side you were filling with water drains through slowly. The new radiator water flows right through as fast as the garden hose can put water into it. No blowback, so that's a good sign.

For fun I cut open the side tanks to see what it looks like.
Doesn't look good, but I've seen much worse. Alot of it washes away as soon as you put the hose directly on it but you can still see the crud in the tubes when you look directly down into them. You know what it looks and feels like to me, is the actual plastic. It has that same slimly flexy disintegration that the upper t-stat to hose fitting I replaced felt like on the inside, you could just peel that fitting away with your fingernail and it felt just like this debris.

If that's really the case where this crap was preventing flow through the tubes then it mabey doesn't bode well for the engine internals, I dunno about VW engines but I've rebuilt some GM motors and they can have some pretty miniscule coolant passages. And what about my "aux" radiator...did I read somewhere where those aren't even available anymore? Mine doesn't leak and holds pressure and vacuum and I also just removed the t-stat hose leading to it and water flows right through there without problem. It's tubes look a bit bigger. 
Perhaps a good old fashioned coolant flush agent would have cleaned this out. But it's difficult to do on this car because they don't sell full strength coolant anymore (at least not from VW) and if you were to fill this system with water it would be impossible to get it all out without multiple coolant changes. I suppose you could use an aftermarket coolant.

Oh well, onward, install new one, then change the t-stat again and .... fill her back up with my deluxe vacuum filler and please god let it be this!!!!


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## Phaetonlvr (Feb 26, 2013)

Excellent news, it's a real surprise that you have flakes like that in there, haven't seen anything like that on mine. That makes you wonder if someone used some stop leak or other chemicals that caused something in the cooling system to react with it?!

Anyway, I just did the thermostat on one of my W12 a couple weeks ago. What I found out is that a previous owner/mechanic had pinched the thermostat wire between the lower intake manifold and the Aorta-looking rear coolant manifold so make sure the wire is still loose once you got that lower manifold back on. I posted a photo of this over at the main W12 thermostat thread.
F265 Map Controlled Engine Thermostat Replacement (W12 -...


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## rocco_16v (Dec 31, 2007)

I've seen this same reddish gunk form when the OEM (G12 IIRC) coolant reacts to water that is either not destilled or other type of coolant was added. 

At least this was my experience on an older MK4 VR6 I bought some years ago. The previous owner used non destilled water to refill the coolant system. So when I bought the car it was not cooling properly (hence the low price). Had to flush multiple times and fix the source of the leak (the auxiliary pump hose).

Sent from my Nokia 3.4 using Tapatalk


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## 73blazer (Feb 19, 2020)

Well perhaps the VW coolant is more sensitive to that kind of stuff, wouldn't surprise me. 

Making excellent progress here, new radiator is in. 
I removed the top end to get my "modified" (half open) t-stat out and another brand new in in. The wire's under the rear coolant passage, yes, I noticed that before IIRC that lower intake won't really even feel seated unless that wire is under that pipe. Still don't like those upper intake bolts 7nm + 1/2turn, I get about 1/3 turn before I get really nervous and stop, and I think the short front one is about had it. 
Anyway, intakes all back on and top end buttoned back up I think I knocked that out in 2.5hrs. Of course it's easier with the coolant already drained and the carrier still in service position. And of course i've done it twice in the last 8 months. 

Just need to put the fans back and get the carrier and front end back together and should be able to fill her up and give it a whirl!! 🤞🤞


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

73blazer said:


> And what about my "aux" radiator...did I read somewhere where those aren't even available anymore? Mine doesn't leak and holds pressure and vacuum and I also just removed the t-stat hose leading to it and water flows right through there without problem. It's tubes look a bit bigger.


There is at least one used W12 aux radiator on eBay if you need it. It sounds like yours is good though.

Good progress and hope the new radiator fixes it.

Good luck.

-Eric


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## Phaetonlvr (Feb 26, 2013)

The aux radiator is still available, I think I bought one last year but might have to come from Germany. 

Funny you mention the short intake manifold bolt. I just broke that one couple weeks ago, just like in the original T-stat thread in the FAQ section. Of course it was the last bolt I tightened and same as you, I only go to 7nm plus 1/4 turn. I was really bummed for a moment but it turns out they are pretty easy to extract as the material is pretty soft and due to the low torque they come out easy with an extractor I had laying around. I used a center punch, then drilled a small hole and then used an extractor and it came right out. Fortunately I had a new spare bolt, should have just used that one right away.


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## 73blazer (Feb 19, 2020)

Yeah even new I don't think that short one needs the "1/2" turn. The others are much longer and able to stretch, the short one just wants to break. 

Mostly back together except for the front facia. Pressure checked at 20lbs for 45mins, needle never moved. Vacuum check at 25hg for 1/2hr, no movement...so I filled her up...again...with fresh G13. One thing I can be sure of is I should have a full coolant change now after draining and refilling 3 times.


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## Phaetonlvr (Feb 26, 2013)

Agreed, I think it's a design flaw with that short one, just not the right material for that application.


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## 73blazer (Feb 19, 2020)

Well. Success!!!!

I could tell right away when the oil temperature didn't go past 200. Usually the coolant temp would go to 200f...stay for a while, then the oil temp would rise slowly to 200f and keep going up to 210-220f, when oil went past 200f, so would the coolant temp. If you were moving with my modified t-stat it would maintain 200F on oil and coolant or so barely, but as soon as you got stopped idling it would start going up. I ran it for 30miles, then idled it in my drive for 15mins and no overheating, oil temp remained below 200, coolant temp pegged at 200F. For final proof, I turned the A/C on full at idle, that would send it to overheat in a near instant before, oil and coolant temps stayed right at 200F. I think I can finally say with confidence, it's solved.

What an epic journey this has been. Thermostats, sensors, 3d printing broken fittings, hoses, radiators, block off plates water pumps tensioner's ,...I basically have a whole new cooling system! Well, at least the main circult.

But now I have a new problem, the hood latch cable seems to have busted or I didn't hook it back up right, it was kinda munged up to begin with and was always a bit tough to pull that handle. So...can you get a phaeton hood open when the cable breaks????? I almost feels like it came off the handle on the inside though. (It appears to me you can just remove the 3 screws holding the latch in from the grill and lift the latch out with the hood???

I almost don't even care, the overheating is solved!!!!!!!


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

73blazer said:


> Well. Success!!!!


Great work. 



73blazer said:


> But now I have a new problem, the hood latch cable seems to have busted or I didn't hook it back up right, it was kinda munged up to begin with and was always a bit tough to pull that handle. So...can you get a phaeton hood open when the cable breaks????? I almost feels like it came off the handle on the inside though. (It appears to me you can just remove the 3 screws holding the latch in from the grill and lift the latch out with the hood???
> 
> I almost don't even care, the overheating is solved!!!!!!!


Yes.

If you can still open the hood, deal with it now. If you can't, there are a few threads but here is the main thread:

(4) Release Handle not opening Hood / Bonnet Latch | Page 2 | VW Vortex - Volkswagen Forum 

Another:

(4) Hood release cable | VW Vortex - Volkswagen Forum

There is another where a W12 owner managed to grip the cable from below. It may have been Stephan. 

Here are my search results:

(4) Search results for query: hood | VW Vortex - Volkswagen Forum


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## 73blazer (Feb 19, 2020)

the hood is closed for my test drive.  i opened twice after putting it together. Third time the handle just pulled and something popped and then the handle feels like nothing is attached. . I think the screws come out from the grille from the threads and what i can see. bit it really soinded and felt like .it came undone from the inside handle. I'll loom later. I'm still celebrating no overheating!


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## Phaetonlvr (Feb 26, 2013)

Excellent news about the cooling issue being solved!! Bummer about the hood latch but that shouldn't be a big deal in the big picture. I'd guess that the cable might have jumped out of the connector piece that sits just inboard of the LH top radiator hose and is clamped to the radiator support structure. This is were you would disconnect the hood release cable from the short cable that is part of the actual latch. it's a narrow long plastic housing that pops open and then you can take the hood release cable out which is what I assume has happened. You might be able to get from it from below if you take the front belly pan cover off. It might be a tight fit to get your hand up there. I think there's also a way to hit the actual latch release from below but I have never had to do this, this might be described in one of the threads that Eric posted. Also look at Phaeton hood latch photos on Ebay to get an idea how it looks like from every angle, unfortunetly I don't have a good photo of one. Good luck.


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## 73blazer (Feb 19, 2020)

I got the hood open by removing the three latch bolts from the front, a bit tricky to get that cover off and get at the bolts, but as with most things on this car, doable with some..... patience. And lucky for me the latch wiring was already busted, disconnected and taped up elsewhere by somebody else I had just ordered a new one of those so I didn't have the wiring to deal with ( i never noticed the red hood open display on the driver IP screen until I found that wiring and realized it was supposed to be on that latch but the plastic body was all busted up, someone just taped it up in the hood closed position not connected to the latch) , once the three bolts were out the hood just lifted right up with whole latch assembly and the disconnected stub cable with it.

Yeah, I did not know that cable came apart there, that would make the carrier to service position alot easier than what I was doing, which was removing the latch. Mine actually looks busted there.
Dammit I hate taking that left side air inlet out, it's a royal pain to fish that in there and get it seated properly in the gasket, with the carrier in service position it's super easy, but not now! Oh well, I can do it, I've done it before.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

That is a pain. The left side air snorkel on 7579 was chewed up so I got a used one on eBay and it took forever to get it to cooperate. It didn't help that a previous owner hadn't even attempted to hit the mark and the gasket was all misshapen.

I always have a b1tch of a time with the intake elbows between the air filter covers and the throttle bodies.


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## 73blazer (Feb 19, 2020)

yeah those air horns are troublesome but some.bloody knuckles and time..they go in.
I finally was able to got a good shot of my 3d printed fitting while the carrier was in service position and the intake off. 











As a pay it forward kind of guy I am , and my deepest thanks for the help in this thread, I will send my two best Phaeton contributors Eric and Stephan a fitting. Just PM your address and they will be on the way!. If anyone else wants (or needs) to buy one they're available on k5obsolete.com. No more overheating!!!!!!


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## Phaetonlvr (Feb 26, 2013)

Congrats on getting the hood open without much damage!



73blazer said:


> Yeah, I did not know that cable came apart there, that would make the carrier to service position alot easier than what I was doing, which was removing the latch. Mine actually looks busted there.


The get the carrier in the service position you just have the slide the bracket off the carrier and it will have enough slack to let the carrier move forward. You only have to disconnect the hood cable when you take the whole assembly off like I did in the photos above.


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## Phaetonlvr (Feb 26, 2013)

53PL-50AAA-VW611BAN said:


> I always have a b1tch of a time with the intake elbows between the air filter covers and the throttle bodies.


As much as I love the W12s, this is the one task that I always HATE the most. Getting the elbows off is doable but getting them back on is just never easy. For me the best way to get them on is to leave them attached to the upper part of the air filter housing then get the elbow onto the intake before lining up the air filter housing to the bottom housing. It really helps if you back out the screws of the upper air filter housing all the way out so the stay up, makes aligning it with the filter and bottom part a lot easier!


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## Phaetonlvr (Feb 26, 2013)

73blazer said:


> As a pay it forward kind of guy I am , and my deepest thanks for the help in this thread, I will send my two best Phaeton contributors Eric and Stephan a fitting. Just PM your address and they will be on the way!. If anyone else wants (or needs) to buy one they're available on k5obsolete.com. No more overheating!!!!!!


That fitting is looking great and it's very generous of you to gift one to Eric and myself, much appreciated!! I'll get you the info via a PM.

Btw, one of my W12s has the same rubber cover over the PCV hoses and they seem to be working great in keeping oil from seeping out. I assume it's aftermarket since my others just have the regular plastic hoses but no sleeves?!


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

73blazer said:


> yeah those air horns are troublesome but some.bloody knuckles and time..they go in.
> I finally was able to got a good shot of my 3d printed fitting while the carrier was in service position and the intake off.


Looking good. Great progress!



73blazer said:


> As a pay it forward kind of guy I am , and my deepest thanks for the help in this thread, I will send my two best Phaeton contributors Eric and Stephan a fitting. Just PM your address and they will be on the way!. If anyone else wants (or needs) to buy one they're available on k5obsolete.com. No more overheating!!!!!!


Wow! Thanks. Sending you a PM.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

Phaetonlvr said:


> As much as I love the W12s, this is the one task that I always HATE the most. Getting the elbows off is doable but getting them back on is just never easy. For me the best way to get them on is to leave them attached to the upper part of the air filter housing then get the elbow onto the intake before lining up the air filter housing to the bottom housing. It really helps if you back out the screws of the upper air filter housing all the way out so the stay up, makes aligning it with the fitler and bottom part a lot easier!


I also back the screws out so they barely hang on. I found that if they stick down at all, they catch on the lower housing.

For the elbows, I use my clamp pliers and slide the clamps to a flat area on the elbow above the clamp but below the accordion part. The top side also has a flat area.

For the right air filter, I disconnect the hose going to the radiator overflow tank from said tank. Sometimes I remember to place it so it doesn't drip but usually I remember after it has started dripping.

For the left side, I disconnect the extra hose on its elbow. I remove both elbows completely.

I pop the MAF connector on each cover using my special VW connector tool. I also pull the MAF wiring out of its clamp on each cover and move them out of the way. They will just pull up.

I position the air filter cover loosely and position the elbow so that it's at an angle at both the throttle body and the MAF. I wiggle them until the elbow is firmly seated at both ends then I move the clamps back into position. It's one of those exercises where it usually doesn't go right the first time and I sometimes have to take a break. Then it just pops into position like that's what it wanted to do all along.

After the elbow decides to cooperate, I tighten the screws on the air filter cover and reattach the hose for the overflow tank and/or the left "extra' hose. Then I plug in the MAFs and re-clamp the wiring to the covers.

-Eric


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## invisiblewave (Sep 22, 2008)

I never get tired of looking at that W12 engine with the intake manifold off. Is it engineering or art?? Congrats on the cooling fix, the harder the job, the more satisfying it is to drive the car thereafter!


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## Phaetonlvr (Feb 26, 2013)

Eric pretty much summed up the process, I usually do it the same way but it's never just a smooth task regardless of how many times one has done it before.


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## 73blazer (Feb 19, 2020)

drove my car 530mi today at mostly 60f or so. It's the first time I've driven it long distance not at night. It's definitely made for the long trip. The sun side people the climate vents opened and blew some a/c while the shady side people get heat. It's amazing how the climate works its the first auto climate system that actually works. Air is emanating from other places and as the driver at one point when it was 65 and i was in the full sun the far drivers vent opens and doesn't go crazy and freeze your arm resting on the door sill but just keeps the crap in the sun at bay at the proper temperature. It must have several sensors to be able to do this.
but zero hint of overheating. A pleasure to drive you feel refreshed after 500mi.


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## 73blazer (Feb 19, 2020)

a


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## Phaetonlvr (Feb 26, 2013)

Excellent news and you finally get to enjoy what driving a Phaeton is all about!


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## dlouie (Oct 31, 2008)

Been a long time since I checked. Glad to hear the issue has been resolved. Congratulations.

Damon


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## 73blazer (Feb 19, 2020)

Put a new hood latch and secondary release cable (main cable to latch) in today, and...wow...hood opens without cringing anymore! It was always hard to open,every time you pulled the handle it just felt like way too much resistance, now it's very smooth. I think something was wrong with that cable or the latch before as it opens far easier now. 
The latch itself I replaced even though the latch was fine it was the electrical to it, it was never connected I noticed someone had broken it before and taped it up in hood closed position. You could have just bought the latch electrical by itself but the latch with the electrical was $2 more go figure...so..it all works now, very well. 
I also bought a new grille and got apparently a 2006 one as VW seems to have consolidated their service parts for anything that fits is a good number. Mine was cracked in a couple places and the logo was already missing fingers before I had to remove it to get the hood open from my broken release cable. I was using strategically placed tape and glue to keep to together but it was a constant nuisance and the chrome on my grille was all bubbled about 15%. New one was only $219 surprisingly. I've seen used ones for not much less with broken tabs and missing logos. 












The cooling problem alone adds to a staggering $3131.01 and thats me doing all the work, no shop time $ included here. 
























Adding in new wheels, two new sets of tires, and various other general maint I've done to it, The Phaeton has steadfastly become the most expensive vehicle to maintain in my history of vehicle ownership. At a mind bending 78.5c/mile to operate in maint alone. I don't include original cost, fuel or insurance costs in here. Nothing else is even close, my next high roller is my 1970 Impala at 22c/mile but it's not really fair to compare that because I've done alot to it and it only gets driven 1000mi/year or so. The next closest every day driver was my 1997 K2500 Chevy diesel at 7.9c/mile. 78.5c/mile is.....holy [email protected]%^@.


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## Phaetonlvr (Feb 26, 2013)

Your Phaeton is looking great now! The numbers are pretty interesting but so much depends on how many miles you'll be driving trouble free going forward. I just did a quick calc with the same methodology and my '05 V8 is at just under 14c/mile (38k miles under my ownership) while one of my W12s is about 42c/mile (only driven 15k miles under my ownership). Of course I maintain mine to a higher standard than your typical owner of a daily driver so there would have been potential to save. The other factor is that none of mine are driven the yearly average in the US which I think is around 12k/year. Anyway, hopefully you'll have many trouble and stress-free miles coming up which should lower the per mile cost!

Btw, some of you part prices are pretty low, even lower than the online VW parts dealers? Are you using a local VW dealer with a special discount?


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## 73blazer (Feb 19, 2020)

Some are Jim Ellis VW parts, some are vwpartsvortex and alot of them were local. Which ones are you talking about? I don't find anything particularly low when it comes to VW parts.


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## Phaetonlvr (Feb 26, 2013)

I think it was the grille and the front belly pan.


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## 73blazer (Feb 19, 2020)

The grille was vw parts vortex. The belly pan was Jim Ellis. My front pan was missing the two air ducts and cracked. and my rear pan was gone completely.


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## Phaetonlvr (Feb 26, 2013)

Looks like the prices have gone up, was thinking about getting the belly pan for one of mine.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

Phaetonlvr said:


> Looks like the prices have gone up, was thinking about getting the belly pan for one of mine.


I have saved searches for both belly pans in eBay by part number.

I have only seen ratty used ones or super expensive new ones since I saved the searches.
I check periodically and get emails.

There is a used 3D0825236 and two new ones on eBay today.


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## 73blazer (Feb 19, 2020)

Phaetonlvr said:


> Looks like the prices have gone up, was thinking about getting the belly pan for one of mine.


I've noticed twice now when I ordered something the price jumped right after I ordered it, like they suddenly realized they had the wrong price listed or something. Like that grille jumped from the $219 (i listed $225 with it's share of the shipping) I paid to $260 now


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## Phaetonlvr (Feb 26, 2013)

That's weird with the pricing but good for you! When it comes to the front belly pan it's pretty much a given to buy a new one. I haven't seen any used ones that are worth considering. I might have to bit the bullet eventually.


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## 73blazer (Feb 19, 2020)

Holding for a couple thousand miles now. 😁
Today was a roasting 91F here, my wife and I drove 50miles to pick up my parents another 10 to get my brother and from there another 30 to a buddies house for a party and all back later. Full compliment of passengers, everyone nice and cool with their own zones (my mom likes it waaaay warmer than most) and ventilated seats in the rear (well, except the middle guy in the back). Not a hint of overheating and my 3D printed fitting has 6-7months on it now and it's holding under heat, cold, heat/cold cycles. The sunroof switch broke though but I think I can do the pen body trick to fix that. It still spits efficiency below threshold catalyst bank 4 every 1000mi or so, I bought the spark plug valve cover gaskets in an attempt to mabey fix that. But other than that everything else seems working pretty good on it. I think it's just happy to be used!


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## Phaetonlvr (Feb 26, 2013)

That's excellent news! I just did a 2,800 mile road trip with my blue W12, not a single problem. However, my silver W12 developped a coolant leak at the auxiliary coolant reservoir which looks like it has a small design flaw. I got a new one on order and will write a new thread showing what the problem is, stay tuned


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## PowerDubs (Jul 22, 2001)

Cat efficiency- swap maf positions - and drive the car hard- floor it at every possible chance to the highest load, until the highest rpm, for the longest time period you can.

Carbon kills. Cats. O2 sensors. Spark plugs. Piston crowns. Piston rings.

Italian tune up means more today than it did 40-50 years ago. And still works, better than ever.


Sent from my iPhone using Tapatalk


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## 73blazer (Feb 19, 2020)

I've swapped the MAF's, and also the engine controllers and put new spark plugs and checked the coils and fixed a couple leaking emissions line and put new breathers. Same bank, same error. When I first got the car last year it would come every 50miles, driving it..well not hard, but 90% of my driving is long distance freeway or state highway, and it's been driven to it's capacity a number of times, that has delayed the code to every 1000mi or so, but they still come. There was evidence of oil in the plug hole last time I was under the manifold, so my thinking was next up to change the spark plug valve cover gaskets.


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## Phaetonlvr (Feb 26, 2013)

Since this thread is about overheating I figured I post a link to my thread about the leak in the secondary coolant reservoir of W12s. 
W12 Supplemental Coolant Reservoir leaking


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