# W12 - oil pressure! Stop engine!



## AJL44 (Mar 23, 2015)

I've had the warning come up a few times recently. Scary, to say the least! 

It happened before some time ago. At the time I had the engine flushed and refilled with new oil and it didn't recur until this week. It usually shows for a few seconds (up to a minute) then goes off. Today it's been much more regular and staying on for longer so I've stopped using the car until I can get the matter investigated.

Does anyone have any idea as to what might be causing this....oil pump, blocked pipe somewhere or maybe a faulty sensor? 

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## DugSms (Apr 23, 2018)

AJL44 said:


> I've had the warning come up a few times recently. Scary, to say the least!
> 
> It happened before some time ago. At the time I had the engine flushed and refilled with new oil and it didn't recur until this week. It usually shows for a few seconds (up to a minute) then goes off. Today it's been much more regular and staying on for longer so I've stopped using the car until I can get the matter investigated.
> 
> ...


Have you checked the oil level?


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## AJL44 (Mar 23, 2015)

DugSms said:


> Have you checked the oil level?


I have, yes. It shows normal and not low. I'll check it again tomorrow though. 

In any event, there is a separate low oil warning as far as I'm aware. 

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## DugSms (Apr 23, 2018)

AJL44 said:


> I have, yes. It shows normal and not low. I'll check it again tomorrow though.
> 
> In any event, there is a separate low oil warning as far as I'm aware.
> 
> Sent from my BBB100-2 using Tapatalk


My guess is that the oil pressure sending unit is bad. I think there is a procedure to check it’s operation, but I don’t know if off hand. 

Have you noticed the oil temp behaving differently? Heating up more quickly perhaps?


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

I would suspect spurious warnings first.

My Phaeton W12 in storage has a dead left battery and it keeps telling me that it has a Workshop Fault Level! that goes away after the engine is running a few minutes and the car raises.

I have to drive in a figure 8 to get rid of the Electronic Stability Control warning. The trunk lid also refuses to open electrically. I may end up buying a new AGM battery but I haven't had a chance to properly charge it yet. 


I would suggest charging the batteries first. The starter battery is probably full. Allow at least 24 hours for the left battery on your charger's AGM setting on trickle.

If you have VCDS, scan and save that scan. If you don't have an emissions inspection due before the end of this month, reset all codes. I would go into both engine controllers and reset them individually. I would run a new autoscan and reset ALL DTCs.

If the AGM battery is indeed low, there are probably multiple faults in almost every controller.


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

Also read my thread on the other W12 I own:

https://forums.vwvortex.com/showthread.php?9238675-Possible-instruments-glitch


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

Our Phaetons are getting old. My W12s are both 2004s and your W12 is a 2003. 

For electrical problems:

I don't know which is more likely, old sensors, old wiring, old controllers or a combination of all of the above. Any car that old is bound to have some wiring issues just from current flow. At lest with VCDS we can reset the controllers without having to disconnect and reconnect each and every one every time. 



It could also be an actual problem but if it is you would want to remove the engine and go through it. It could just be the oil pump but you would want to get the oil passages completely cleaned out which I don't think you can do with the engine assembled. 

There was a guy on eBay with W12 crate engines but he said they all got sold to China. Since your W12 is historic, I would try to save the original engine.

The fact that you had the engine flushed reduces the possibility that an oil passage is clogged.


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## AJL44 (Mar 23, 2015)

AJL44 said:


> I have, yes. It shows normal and not low. I'll check it again tomorrow though.
> 
> In any event, there is a separate low oil warning as far as I'm aware.
> 
> Sent from my BBB100-2 using Tapatalk


Checked the oil and it was showing at the top of "minimum" so topped it up with about a half litre of Castrol Edge 0W-03. Still getting the same warning.


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## AJL44 (Mar 23, 2015)

DugSms said:


> My guess is that the oil pressure sending unit is bad. I think there is a procedure to check it’s operation, but I don’t know if off hand.
> 
> Have you noticed the oil temp behaving differently? Heating up more quickly perhaps?


I'm coming to the same conclusion, to be honest. The unit seems to be very cheap and common to lots of things but I'm not sure how easy it it to get at. Probably need to remove the whole front end to get at it 

Oil temp and engine temp seem to be unaffected. No change in behavior at all as far as I can tell.


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## AJL44 (Mar 23, 2015)

53PL-50AAA-VW611BAN said:


> I would suspect spurious warnings first.
> 
> My Phaeton W12 in storage has a dead left battery and it keeps telling me that it has a Workshop Fault Level! that goes away after the engine is running a few minutes and the car raises.
> 
> ...


Doubtful it's the battery. The AGM one is relatively new and has recently been fully charged as I was messing about fitting the fridge recently so had it on charge when I managed to run it down too much a few times. Having said that, I think I may leave it on charge on the "slow" setting rather than "fast" for a couple of days just to make sure.

"Level Fault" is the first spurious fault that shows on either of my Phaetons when the battery gets a bit low but I haven't seen that one in a while.


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## AJL44 (Mar 23, 2015)

53PL-50AAA-VW611BAN said:


> Our Phaetons are getting old. My W12s are both 2004s and your W12 is a 2003.
> 
> For electrical problems:
> 
> ...


I'm definitely keeping the original engine. At some point I'll have the engine dropped and totally overhauled and cleaned and I'll get things like O2 sensors replaced. I also have an alternator I got for £40 that I'll get refurbished for a couple of hundred quid rather than the £1,300 that VW want for one and do the same with the oil and water pumps done. House extension first though 

I think I'll get it flushed again just to make sure though.


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## invisiblewave (Sep 22, 2008)

The oil pressure switch on the W12 is on the side of the filter/cooler housing. Aftermarket ones are $5.....


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## PowerDubs (Jul 22, 2001)

A gunked up oil pickup is easy to check for and clean if needed.

Granted a lot of quarts to drain to check- but better than cooking your engine

Not going to lie- your comment saying the warning usually stops in a minute, but lately takes longer scares me.

Low oil pressure is the worst thing you can do. Meaning the warning should invoke immediate shutdown no questions asked. As is- turn off and coast to the side of the road. 

You aren’t going to fix a W12 engine from any issues done from low/no oil getting where it needs to go. Doesn’t matter if it is top or bottom end, might as well junk the car.


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## Prince Ludwig (Mar 24, 2007)

It's also worth noting that VW recommends that its Alusil engine blocks are replaced in their entirety if tension is taken off the main crank bearings. That's why there are no parts for the short block available in ETKA other than a complete unit.

Harry


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

Prince Ludwig said:


> It's also worth noting that VW recommends that its Alusil engine blocks are replaced in their entirety if tension is taken off the main crank bearings. That's why there are no parts for the short block available in ETKA other than a complete unit.
> 
> Harry


Wow, that's good to know Harry.

I guess a traditional rebuild is out of the question. 

What does the future hold for collectors who need a rebuild and want to keep it all numbers matching?

OP, I retract my previous recommendations. 

-Eric


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## invisiblewave (Sep 22, 2008)

I think the days of maintaining cars for 50+ years have passed Eric. There are a multitude of reasons why the Phaeton isn't a car that you'll be able to keep running on those sort of timescales, and the same likely goes for most, if not all, modern cars.


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## AJL44 (Mar 23, 2015)

invisiblewave said:


> I think the days of maintaining cars for 50+ years have passed Eric. There are a multitude of reasons why the Phaeton isn't a car that you'll be able to keep running on those sort of timescales, and the same likely goes for most, if not all, modern cars.


I'm a bit lost with this and the issue of releasing tension from the bearings, etc. Why is this ruinous to the engine block? 

No offence to anyone but I'm always skeptical when people say that things can't be saved.


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## Prince Ludwig (Mar 24, 2007)

AJL44 said:


> I'm a bit lost with this and the issue of releasing tension from the bearings, etc. Why is this ruinous to the engine block?
> 
> No offence to anyone but I'm always skeptical when people say that things can't be saved.


It's not a question of things that "can't be saved", it's a question of whether they can be saved economically. The electrolytic capacitors in cars have a design lifespan of about 15-20 years and after that can start to dry out causing either strange behaviour or outright failure. Replacement control modules will probably have similar ages and although I'm sure there are specialists who can diagnose and repair faulty components, it's not going to be cheap.

With regard to the engine block, VW states that taking the tension off the mean bearing bolts causes the block to expand slightly and create distortions along the crank centreline. I'm sure if you ask an engine rebuilder they'll tell you that it can all be rebored and made acceptable again but the fact of the matter is that replacement internal components for W12 engines below the short block are not available from VW.

Harry


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## invisiblewave (Sep 22, 2008)

Right. Almost anything can be done, given the necessary resources, but given the complexity of the Phaeton (and other modern cars), the cost of keeping them on the road will become astronomical. No doubt some people will go to heroic lengths, there's a guy across the road from me who has just removed the engine for a rebuild from a 1990 Supra that is basically a pile of junk. Of course, that's a relatively simple vehicle compared to ours, I can't imagine trying to do the same thing to a Phaeton in 20 years' time.


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

Prince Ludwig said:


> It's not a question of things that "can't be saved", it's a question of whether they can be saved economically. The electrolytic capacitors in cars have a design lifespan of about 15-20 years and after that can start to dry out causing either strange behaviour or outright failure. Replacement control modules will probably have similar ages and although I'm sure there are specialists who can diagnose and repair faulty components, it's not going to be cheap.
> 
> With regard to the engine block, VW states that taking the tension off the mean bearing bolts causes the block to expand slightly and create distortions along the crank centreline. I'm sure if you ask an engine rebuilder they'll tell you that it can all be rebored and made acceptable again but the fact of the matter is that replacement internal components for W12 engines below the short block are not available from VW.
> 
> Harry


Dang, VW Vortex ate my original reply. 

I wrote a bunch of stuff about home electronics and how specialists replace old components with more robust components all the time. There are even companies that advertise that they replace old components and make your home electronics better than they came out of the factory. 

I have little doubt that dodgy car electronics could be rebuilt the same way. Sending the control units out for repair and upgrade might lessen the multiple errors we seem to get every time the AGM battery blinks. 

As far as the engine block expanding, that's a weak excuse. Any good engine rebuild includes line boring the main bearing journals unless they are within specifications and the caps don't need to be trued or replaced. That's standard practice on cast iron blocks. 

If VW doesn't sell internals for the W12, that doesn't bode well for the future. 

-Eric


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

invisiblewave said:


> Right. Almost anything can be done, given the necessary resources, but given the complexity of the Phaeton (and other modern cars), the cost of keeping them on the road will become astronomical. No doubt some people will go to heroic lengths, there's a guy across the road from me who has just removed the engine for a rebuild from a 1990 Supra that is basically a pile of junk. Of course, that's a relatively simple vehicle compared to ours, I can't imagine trying to do the same thing to a Phaeton in 20 years' time.


That's nothing new. A quality restoration of a Jaguar E-Type was over 6 figures when I asked 14 years ago. That's $100K+ back in 2004. 

At the value of a concourse level E-type back then it just wasn't worth the cost to restore them if you were worried about "value". Even now, it's only the value of very early E-types that justifies the cost of a good professional restoration. It's cheaper to just buy a fully restored E-Type than to get yours restored. It is worth it to many people or the restoration specialists would go out of business. 

Back when I was a tadpole, there was an article in the newspaper where they interviewed a guy who restored Model A Fords. He said they cost $10,000.00 to restore but were only worth $3,000.00 when fully restored. 

I had a coworker with a Pinto. Talk about complex. Ford took a basic car and piled options on top of it. This poor car had A/C, power brakes and power steering which was added to the base engine so you had to get that stuff out of the way to work on it. You could barely make out the little engine under all that stuff. 

I can barely reach the left rear spark plug on my old Ford because the brake booster is in the way. 

That old Ford cost me less to buy than I paid for its tires. 

The only true problem with restoring Phaetons in the future will be the lack of new parts unless VW Classics makes them (and sells them to us Americans). We will have to rely on used parts for most body and interior parts.

There won't be hoards of aftermarket companies stepping up to supply the hobby like with American muscle cars. I could build a new 1969 Camaro and probably not need any used parts to do it. Chevrolet even sells crate engines on its website. 

The complexity is mostly the electronic doodads. 

The Phaeton is a system and like any system it can be broken down into subsystems. 

If our cars were more common, we could probably get rid of our air bag suspensions like Mitsubishi 3000 GT/Dodge Stealth owners can. Of course it helps that those were also available with conventional suspension.


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## zoltan99 (Jul 22, 2013)

You can check the oil pressure with a mechanical gauge at the sender port to see if the sender is bad. Or, just replace it. I had the dealer check mine (just because of the age and mileage, not because of any warning) and they found great pressure.

It's more than likely a wiring fault or sender fault if you never ran the car low on oil and have been changing the oil. It's probably fine. 

Also, while VW recommends whatever they recommend, they also recommend replacing the rotors instead of turning them, and they recommend replacing them with each pad change. After 4 and a bit years and 100k miles I just replaced the set for the first time last year.
Alusil is not special. It's cool, it's fine, but, they might be embellishing a bit because it's a special engine series, the W engines. 
I haven't found the bearings, but, they don't offer them for the Phaeton 4.2, but they offer them for the B7 RS4 4.2, the B8 S5 4.2, the C6 A6 4.2, the R8's 4.2, the S8's v10 and the Q7's 4.2 V8 and the Touareg's 4.2, all under separate parts listings, all under the part number 0791057701G GLB (for a perfect factory size bearing, there are sub part values for different levels of wear listed by color of the measuring system used..forget what it's called.)

See here and here:
https://www.jimellisvwparts.com/sho...sembly=745251&ukey_make=1066&ukey_model=15578
https://www.ecstuning.com/b-genuine...ecting-rod-bearing-priced-each/079105701gglb/

Those are con-rod bearings, they also offer crank main bearings for those engines as well.

I have no idea why Phaeton parts are harder to come by..but I'm just the kind of person that would buy a couple of bearings just to see the differences and if they fit. It's a 4.2 5v. The engine covers and coils and other parts swap over, just accessories and all don't due to packaging.

There are a few cars with the 6.0 W12. Not many...but I'm sure Bentley bearings fit as the engines are actually cast as Bentley engines. the 03-10 is basically a Phaeton engine, mechanically, internally that is. Everything I've ever seen supports that, maybe I haven't seen enough. Surely different camshafts and ECU programming and things, I haven't heard of any other significant differences.

For some reason these guys have 6.0 W12 con rods, maybe they'd be able to do bearings: https://www.cleggengine.com/vw-phaeton-6-0-w12-connecting-rod.html

Find Audi A8 W12 D3 gen bearings, (04-10 I think,) and you find Phaeton and Continental GT bearings. It's silly that they put a blackout on Phaeton 4.2 parts when they're the same engines.

Maybe I'm wrong. I know I'll be driving my Phaeton long enough to find out and I know that unless there's a good short block on eBay for less than the price of a rebuild, I'll be finding out if the same bearings that fit the RS4, S5, A6, Q7, A8, R8, and Touareg will also fit my Phaeton. Who knows. Maybe they don't. Maybe they really, really don't. They're all permutations of the 5v 4.2, I don't see the weird rear-timing S4 version on there, who really knows. I'll spend money to find out just because I'm that kind of guy.

I don't see why they'd create special conrods and crankshaft parts for a Phaeton when they reuse the same parts throughout all of the other same-model-year 4.2's. It seems more like they never offered these parts for Phaetons for arbitrary reasons. I haven't seen it to have some special oiling system (except for the W12 dry-sump)

https://www.sunnen.com/NewsDetails.aspx?NewsID=11



All of this is beside the point. If nothing bad has happened to your engine it's incredibly unlikely it's anything but a spurious error, or a sender unit failure. Don't take a chance, get it checked or replace the sender and check the wiring, or if that part replacement doesn't help, get a mechanical gauge on the thing to really make sure there's pressure...but unless it's been run seriously low, it's doubtful anything is wrong.


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## zoltan99 (Jul 22, 2013)

PowerDubs said:


> A gunked up oil pickup is easy to check for and clean if needed.
> 
> Granted a lot of quarts to drain to check- but better than cooking your engine
> 
> ...



Powerdubs speaks the truth. That's scary. That might be a serious problem..or a gunked up sender. Don't chance it. Also make sure you're using the right weight of oil. 0w-30 is not right and for these engines you should not change it up.

Don't run with low oil pressure. Shut it down and get it checked, cold and warm. Otherwise you're buying an engine.

I mean, I'm the kind of person that'd buy an eBay engine and send it, or find bearings for a conti GT or Audi A8 W12 if I could...rather than junk it.


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## zoltan99 (Jul 22, 2013)

https://www.ebay.com/itm/Engine-6-0...ash=item4d762bb928:g:Rm8AAOSwIrVbLSNR&vxp=mtr

send itttt. Check on your engine first, seriously, but, used engines are a thing. Sad to see these cars go...if there's no accident damage I'd love to save that car. Too bad my Phaeton is just fine 

Looks like the aftermarket has identified that the v8's bearings cross over fine: https://www.ebay.com/itm/Audi-VW-V8...ash=item4b4c5f6227:g:RSIAAOSwoyVbeWXa&vxp=mtr

Running 0w-30 will lower oil pressure at startup - when your engine struggles for pressure most. That's really bad. You may have been clearancing your bearings (killing your engine) during startup. If anything, I'd rather a 10w-30, but, I'd NEVER stray from manufacturers recommendation on oil weight. What weight have you been using? You could possibly save it by putting the OE recommendation back in and leaving it that way.


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## AJL44 (Mar 23, 2015)

Castrol Edge 0W-30 is exactly what comes up on Castrol's online selector when I input the details of my car. 

https://applications.castrol.com/oi...ndation?data=aa76f31f021cbd533c1aff7054984cbf

Now, I don't know whether it's completely filled with that but I topped it up with just over half a litre of it the other day when it was showing a bit low on the dipstick. 

The same oil also comes up for my V8. 

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## Prince Ludwig (Mar 24, 2007)

Castrol's website recommends three oils: 0W40, 5W30 and 0W30 for the W12. However, only 5W30 is approved for LongLife service intervals and I'm pretty sure is the grade that VW recommends for almost all of their cars.

Harry


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

My dealer filled mine up with Castrol Edge 5W-40 and gave me an extra quart for topping off (which is right next to me as I type this).

The mechanics said they use it on all VWs, just like they use the same coolant on all VWs.


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## DugSms (Apr 23, 2018)

53PL-50AAA-VW611BAN said:


> My dealer filled mine up with Castrol Edge 5W-40 and gave me an extra quart for topping off (which is right next to me as I type this).
> 
> The mechanics said they use it on all VWs, just like they use the same coolant on all VWs.


LubriMoly 5w-40 is what I used on my oil change. 
Less cam rattle on startup than before I changed it.


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## AJL44 (Mar 23, 2015)

I've had this issue coming up again - don't worry I've always stopped immediately, switched it off and restarted and it went away.

On checking the invoice from when the oil was last changed it states that it was refilled with 5W30 oil whereas it would seem the general wisdom is that it should have been 5W40. A mechanic I know who works for VW confirms this also. I'm going to get it refilled with the latter. I think I'll also get the sensor changed.

Question: does the car have a pressure sensor that the Rosstech cable can take an oil pressure reading from or is it just a basic "low or normal" switch? If so then I'd like to be able to take readings with the current oil and after it's been changed and note any differences.


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## Prince Ludwig (Mar 24, 2007)

I'm pretty sure 5W30 is the recommended oil for almost all VWs on the LongLife program (something that I don't believe is offered on NAR cars).

Here's a useful flow chart that shows the oil specs for VW engines (and includes the right spec for the V10 and I5 PD engines):










Harry


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## kicku (Apr 8, 2018)

Well,
wasn't left much to check.
As zoltan user said, check first the oil pressure. Should be at cold not less than 6 Bar.
At hot should get lower but not under 5 Bar.
This test will eliminate in one shot any electronic / sensor problem, without need to buy a new pressure sensor. I hope for you I am wrong and will be just a dodgy sensor...
If will be less, than check the oil filter it's not clogged. Change it to be sure.
Anyway, normally the pression is about 8 Bar at cold engine, and should rise instantly when starting the engine, not more than 2-3 seconds. The pressure readings must be done at idle.
As i said in the other topic, the first symptom of bent crankshaft is at very hot engine, will crank very slow or not at all.
The second symptom is the oil pressure drop, due to the streaked bearings. Should be seen mostly at hot engine, because the oil becomes more fluid, the pressure will be lightly lowest, as result the oil pressure sensor will not trigger if the pressure is below 1,5 Bar. Keep in mind this 1,5 Bar. It's very, very low pressure, running at this pressure will destroy the entire engine.
The third, and the last ( was for me ), the screws and caps of crankshaft broken. Found later into the sump, 2 caps broken, 5 bolts in pieces.

I took off the entire engine, changed all bearings with std +0,25, bored the short block, realigned the crankshaft, rebuilt entire engine. The result? Waste of time and money.
Why? Simply, because once the engine start to bent, this does mean it's already got microfractures inside the walls. The result was after the same. When will became warm, it will bent yet again, thus will lead again to torsion around the cranshaft, overheat the bearings and "ciao ciao al motore", as we said here.

I really hope for you I am wrong.

Good luck.


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## snapdragon (Aug 8, 2006)

I would replace the pressure switch anyway. They only last about 10 years in my experience of various cars (not W12) but they give a simple binary output (short to earth) until they eventually give the symptoms described.


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

kicku said:


> I took off the entire engine, changed all bearings with std +0,25, bored the short block, realigned the crankshaft, rebuilt entire engine. The result? Waste of time and money.
> Why? Simply, because once the engine start to bent, this does mean it's already got microfractures inside the walls. The result was after the same. When will became warm, it will bent yet again, thus will lead again to torsion around the cranshaft, overheat the bearings and "ciao ciao al motore", as we said here.


Are you saying the block itself had microfractures and bent when it got warm? Did you have the block magnafluxed?

Did you have the crankshaft magnafluxed?


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## kicku (Apr 8, 2018)

53PL-50AAA-VW611BAN said:


> Are you saying the block itself had microfractures and bent when it got warm? Did you have the block magnafluxed?
> 
> Did you have the crankshaft magnafluxed?


I have no idea if they did it. They said this because wasn't the first time for them seeing this thing.
Anyway i am sure about everything else was right.
The entire oil pump was new ( not a rebuild ), with filter cleaned. All channels for oil inside the long block and head cleaned and inspected to be sure there is no part inside blocking the oil.

After this, took an old long block with 110.000km ( my luck ) from a local dismantler and took off everything from the old engine to the "new" one. So, sensors, oil pump, the head with camshaft and everything on it, every pipe and everything else.
This time, everything ended fine, this engine it's still run without any problem, already done 40.000km with it.


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## invisiblewave (Sep 22, 2008)

If you took all the sensors, etc, doesn't that mean it still might have originally just been a sensor problem?


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## kicku (Apr 8, 2018)

invisiblewave said:


> If you took all the sensors, etc, doesn't that mean it still might have originally just been a sensor problem?


A sensor cannot lock a crankshaft in no way.
When the engine was off the car and did tried to turn the cranshaft at hand, has moved very hard, like something was locking / break it.
Here's a picture of it.



As you can see, the crankshaft has suffered due to overheating.


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## PowerDubs (Jul 22, 2001)

www.ebay.com/ulk/itm/322633130105


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