# My Cam Follower at 50k



## StuMacLean (Aug 9, 2003)

Well, after 50k, i decided that it was time to replace the follower. Glad that I did. The black coating is nearly completely gone. However, I think that i did it in time to prevent any major damage being done to the cam (which looked great).
This is the surface at 50k
















Here's a shot of the side of the unit:








I also measured the thickness of the remaining wear surface. If anyone out there could measure a brand new one, I'd love to see how far I wore through the part.
















So, my car is a bone stock 06' Gti, I watch my oil level between changes, and I drive 95% highway miles. I think I'm fortunate to have a situation that promotes long life for the follower. 
However, this is pretty good evidence that the follower will inevitably fail.I'll be checking mine every 40k if I stay stock, or more often if I begin to upgrade the performance.Hopefully this offers something to the information pool on this topic. Again, if anyone has a good thickness measurement of a stock follower, please let me know.


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## SmithersSP (May 24, 2006)

*FV-QR*

Measuring your follower with a caliper to obtain quantifiable data? I like the way you roll son! 
I'm not sure how thick the OEM follower is. I can ask my VW tech friends to measure one next time they do a cam/follower replacement. Have you considered buying KMD's upgraded follower? A lot of us 130bar HPFP guys are running these. They are .028 thicker than oem.
http://www.kmdtuning.com/index...=1426


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## StuMacLean (Aug 9, 2003)

*Re: FV-QR (SmithersSP)*

I wasn't aware that someone had come up with an alternative to the stock part. Interesting. I'll have to mull it over. 
I think it's great that companies are starting to tackle this problem. Though I would prefer a solution that eliminated follower wear. That's a tall order though.


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## utekineir (Jul 2, 2008)

*Re: FV-QR (SmithersSP)*


_Quote, originally posted by *SmithersSP* »_Have you considered buying KMD's upgraded follower? A lot of us 130bar HPFP guys are running these. They are .028 thicker than oem.
http://www.kmdtuning.com/index...=1426

I'd rather buy 2 oem followers for the same price, (1stvwparts.com ??) that actually have the dlc coating.


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## StuMacLean (Aug 9, 2003)

*Re: FV-QR (utekineir)*

That's true, the DLC probably does a good job until it goes away. 
I wonder if the 0.028in of additional thickness in the KMD part could cause any problems with the fuel pump. This additional thickness would directly shift the pump range of motion 0.028in towards the pump.


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## aeproberts21 (Apr 10, 2007)

*Re: FV-QR (StuMacLean)*


_Quote, originally posted by *StuMacLean* »_That's true, the DLC probably does a good job until it goes away. 
I wonder if the 0.028in of additional thickness in the KMD part could cause any problems with the fuel pump. This additional thickness would directly shift the pump range of motion 0.028in towards the pump. 

That is my major question with their part. It is not stopping the wear on the follower (it is just thicker) and it might actually have other ramifications. I think I would just change my stock follower twice as much.


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## StuMacLean (Aug 9, 2003)

As a follow up to my previous measurement data, I've measured the thickness of a brand new cam follower. 

Remeasuring the old (50k unmodified motor) follower: 










Measuring the brand new follower:









As you can see, my re-measure was off by about .0007in, but I'm willing to chalk that variation up to using a post-it under the followers for this second round of measurements. I didn't want to risk scratching the new follower on the stone. This is more variation that you'd like to see, but it'll have to do for now. 

If a brand new follower is .0802in thick, and after 50k on a stock setup, it only wore down to .0783, for a difference of .0019in. That's not bad. For reference, and human hair is about .002 to .003 in thick! Of course, the DLC probably lasts a long time, so it's difficult to predict the wear rate of the steel alone. 

I bought the car with 19k on it. I'm good about checking the oil level at every fillup, and I just use the normal Castrol or whatever the dealer sells.

I'm planning on checking my follower again soon. I'm at about 75k now, and I went APR stage 1 (jizz in my pants) right after changing my follower at 50k. I'll post follow up data if i end up swapping the new follower in this time.


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## jasejtw (Jul 19, 2007)

That is a very nice Mitutoyo 0-1" Digital Plunger Indicator mounted over a pink granite surface plate. It reads into 50 millionths of an inch... Whats the price tag on that indicator? about 400 or 500 dollars? Ive been looking to get a 50 millionths last word dial indicator from Brown & Sharpe for my job. Price tag on those are about $180 and up. Anyway I guess its probably time for me to pull my high pressure fuel pump and check my cam follower since i have 54K on my GTI and I have been getting a low fuel rail pressure code thrown with stg 1 apr. Anyone wanna help me out and direct me to the sticky for the DIY to pull your HPFP on FSI engines? I know i have seen it before. Also does anyone know the part number and price for a new cam follower?

Also you might get a more accurate reading of the wear on the cam follower if you flip the part over 180 degrees and zero your indicator out on the top of the new cam follower, then put the old cam follower under the indicator and measure to the bottom of the concave surface created by the rotating cam lobe. Just looks like your measuring the part upside down to me. Maybe i am mistaken... I just find it hard to believe the wear on the surface of the cam follower to be less than .002" after 50K. But you are correct, a human hair is about .002-.003. and average sheet of paper is about .004. You can make a metal part grow in size 50 millionths or .00005" fairly easily just by holding it in your hand for a while and getting it warm from the heat of your body. try it with some gage blocks sometime if you don't believe me.


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## StuMacLean (Aug 9, 2003)

Yeah, I like this Miti. I've only seen 50 millionths indicators go for several hundred dollars. If B+S have one for $180 get on it. But, you'll probably want a cert with it.

If you flipped the follower over to measure the wear, you'd let the overall length of the part contribute to your measurement variance. I wouldn't find it had to believe that there could be a .001-.002in difference in length of the overall parts. That difference would show up if you flipped the part over. 

My measurement technique isn't perfect, due to the post it note. However, I'd argue that I'm well within .001 of the real difference in the two parts. So, worst case, about .003 in of wear over 50k. But, we still need to keep the effects of the DLC in mind. That stuff is designed to not wear away. 

And I definitely believe you that the follower could grow 50 millionths by warming it up a few degrees. A 18" gauge block compresses 50 millionths if you just stand it on end! :beer:


As for your sticky requests:

http://www.golfmkv.net/blog/archives/6#
This should get you started. Very thorough.


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## jasejtw (Jul 19, 2007)

Thank you much for the link. And where in the world do you work that has 18" gage blocks? lol most sets only go up to 4". Id figure it would be more practical to buy a CMM if your measuring parts that size, but i dont know. I'm just a young machinist.


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## saaber2 (Jul 15, 2008)

Nice job changing it out when U did. You can clearly see the wear circle developing where so many of these followers break. What oil did you use for the 50k miles and how often did you change it?


StuMacLean said:


>


Here is an example of one with the same wear circle where the surface is only scratched/etched and not yet heavily worn.










and an example that has punched through at the circle:










I'm not clear yet whether that circle develops from the forces of rotation (see example below of a non 2.0 FSI)










Or from the metal being thicker in the center and thinner on the outside (the circle would fall at the interface of the thick and thin portions). This has been postulated on another thread.

Here is another look at the circle at the very early stages of wear. This follower appears totally black (except maybe the very center) when viewed head on. I held it in the light so it would exaggerate the wear.


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## StuMacLean (Aug 9, 2003)

As I stated above, I bought the car used with 19k, but I believe it was dealer serviced by the original owner. And I have my oil changed at the dealer. I believe the dealers use castrol syntec. I also keep an eye on the level, and rarely let it get below 50% on the dipstick. Change every 5k miles.


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## StuMacLean (Aug 9, 2003)

Oh, and yeah, the 18in gauge blocks are definitely not your average tool. I learned about the shinking effect of standing those one end from one of our older engineers here who used to work at a gauge making facility.


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## StuMacLean (Aug 9, 2003)

Update:

So, I pulled my follower out on Saturday. 

Here is the follower I removed, in the motor from 50-75k, running APR stage 1:



















As you can see, it had worn through most of the DLC, and I put a new follower in. 










This follower had a similar amount of wear as the follower that I had in for 0-50k stock tune. Very glad that I checked when I did. I think 25k is a bit too long of a change interval for a stage 1 car. I'm thinking more like 20k or a little less is best. I don't have any evidence, but I believe that once the DLC is removed, the follower and cam begin to wear down much faster.


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## saaber2 (Jul 15, 2008)

Stu, fantastic info.!

Regarding the follower change interval, there are tons of variables such as driving style, power mods, matallurgy, etc. but I wonder how much of a difference oil type and oil change interval make. Certainly the wear is directly related to lubrication, and it's logical that oils with lower anti-wear additives or oils that are worn out and run too long would make the follower wear out more quickly.

Your post above shows the wear in 25k miles really well. As a data point, here is my follower's wear with 25k miles (from 11k to 36k on car)

the first pic is at 11k (note that the lighting accentuates silver color, looking straight on this looks black). The initial wear was likely due to miles on factory fill because since changing to ester-based, wear is almost imperceptible. The second pic is at 36k. Compare the inner "silver" circle from the 11k to 36k one. Very minimal, almost non-existent wear using highly additized ester-based oil. 

at 11k










at 36k


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## JohnJP27 (Jul 24, 2001)

saaber2 said:


> Stu, fantastic info.!
> the first pic is at 11k (note that the lighting accentuates silver color, looking straight on this looks black). The initial wear was likely due to miles on factory fill because since changing to ester-based, wear is almost imperceptible. The second pic is at 36k. Compare the inner "silver" circle from the 11k to 36k one. Very minimal, almost non-existent wear using *highly additized ester-based oil.*


What oil are you using specifically? I just bought an '07 Passat Wagon with 36k miles, so I might want to check the follower and start using the oil you've been using. Thanks! :wave:


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## StuMacLean (Aug 9, 2003)

Saaber, I would also be curious to know what oil you are running. As I stated above, I just run whatever the stealer puts in. I believe it's Castrol Syntec. I might need to make a switch if you're getting that little wear after 36k.


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## rhouse181 (Apr 13, 2008)

Stu, 

Nice job with your long term testing :thumbup:

Saaber runs some flavor of Red Line ester based oil... he has tried a couple over the last few fills, so I'm sure he can provide you the details. 

The wear pattern on the latest follower you removed looks nice and consistent, with no pitting... Its hard to tell whether it exhibits the circular wear pattern that your first follower showed. I remember someone saying that they redesigned/reinforced the inside of the cam follower face to prevent the inner circle from being punched out. You can certainly tell a difference in the wear pattern between the two followers. 

Your caliper measurements are interesting to show how much DLC gets stripped off... but I agree that it would be nearly impossible to develop a model to predict how fast the coating wears. Too many uncontrollable variable...


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## StuMacLean (Aug 9, 2003)

I just took a long look at my second follower (50-75k) to see if I could get an idea about whether or not that "wear circle" was developing. I really can't decide. 

The second follower has worn the DLC away to just about where the wear circle should be. And I can't tell if the border between steel and DLC is the wear circle, or just the transition from steel to DLC. 

I've been told that DLC is very very thin when applied to parts like this. DLC typical coating thickness is on the oder of .00005in. Works been a $hit $how today, but when I get some free time I'll ponder what these measurements mean.


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## saaber2 (Jul 15, 2008)

I'm seeing what looks like 3 bands. The red and the blue areas show the outside bands of the developing "wear groove/wear circle". A little hard to tell from the photo though. Maybe the green and red are the outsides of the groove. But definitely circular bands.


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## jasejtw (Jul 19, 2007)

Has anyone tried taking an indicator to the surface in the photo pictured above^^^ and measured the difference between the outer edge (where the part surface is still black coated and untouched) and measured the difference of depth to the center of the shiny "worn in" surface (the area where the green band and blue arrows are in the photo), and move the part around under the indicator to find to lowest spot of the surface that the cam lobe comes in contact with. And subtract the difference, To find how much the cam lobe wears into the cam follower? Since the surface that rides on the cam lobe clearly is no longer flat and has become concave. Im curious to see how much the material wears/deforms, because after a certain amount of wear from the surface the material is going to start to deform and bend to some degree.

For example, Photo B in Figure 2 of this TSB. Photo C in figure 2 shows normal wear, and photo A shows the worst case situation in which the follower than has worn completely through. 
http://www.kmdtuning.com/store/images/150702TSB(2).pdf


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## XM_Rocks (Jan 29, 2005)

Mine at 52k miles.

07 GTI... at that time 95% of highway miles.

Literally 52k miles in < 2.5 years.


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## StuMacLean (Aug 9, 2003)

Funny you should ask.


> jasejtw
> Has anyone tried taking an indicator to the surface in the photo pictured above^^^ and measured the difference between the outer edge (where the part surface is still black coated and untouched) and measured the difference of depth to the center of the shiny "worn in" surface (the area where the green band and blue arrows are in the photo), and move the part around under the indicator to find to lowest spot of the surface that the cam lobe comes in contact with. And subtract the difference, To find how much the cam lobe wears into the cam follower? Since the surface that rides on the cam lobe clearly is no longer flat and has become concave. Im curious to see how much the material wears/deforms, because after a certain amount of wear from the surface the material is going to start to deform and bend to some degree.


I actually took these measurements the other day:

Here, I've zero'd the indicator at the center of the follower:










And here, I've moved the indicator out to the edge of the remaining DLC:









So, as you can see, on my second cam follower (50k-75k) there's about five tenths (.00055in) of a difference between the height of the center of the follower and the outer edge of the DLC. That's not a lot of depth, but it is significant.

I don't necessarily believe either part (cam of follower) is bending. These followers are hardened steel, and at .08in thick, it's not going to flex much under load.


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## aznsap (Aug 7, 2010)

+1 on what oil saaber is using.


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## jasejtw (Jul 19, 2007)

StuMacLean, Thank you for taking those measurements. I am surprised to see the variation is only 5 tenths and 50 millionths of an inch. That really is very small, I was expecting to see a dip in the center of around .002" or more. I wonder what the Rockwell rating (Hardness scale) of the parts is. Thanks for the info, now i just need to get the motivation to pull my HPFP.


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## deeeGLI (Mar 1, 2006)

While I find all of this info very interesting.I have a question--
What are the indications of a failing follower?

While coming from a 15yr technician background(other manufacturers),and having much experience in all MK1-MK4 aspects,my 2.0t FSI experience is just begining.
I recently purchased an 07' Passat wagon,one owner has about 46k on it.It is the family car and will see very little daily driving.I have to say great it's a great car---However it sounds a little rattlely(is this a word?)at an idle.Not like a bad lifter or anything,has almost a TDI sound to it but softer.I have checked all the run of the mill things,theres no codes,and I have been recently trolling the FAQ's when I have time just to get up to speed on this drivetrain.
I don't wanna get way off topic, but you all seem like you have half a clue,and don't act like douschebags.


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## jasejtw (Jul 19, 2007)

deeGLI, I have a 07 GTI that I purchased new, and i noticed within the first month this kinda, vibration-bump-rattle at idle that the engine seems to have that you are referring too. I would come to a stop and the engine would be idling in neutral and it would seem to bump or shake once every now and then, almost like a soft misfire. I took it to the dealer and complained about this issue, they scan it, test drove it, and could not find any problems with it. It only seems to do it at idle every now and then. The dealerships response was that the car may be trying to save gas so much at idle (ultra-lean combustion mode) that it may be causing this to occur. So i continued to drive to car and drive it somewhat aggressively and it never became an issue. If you can boost your car stock at WOT and it peaks up to 14 psi and holds at 11 psi until high rpms, then i would not be concerned about the idle rattle you feel.

Idk if someone else can tell us more about the cause and reason why this engine seems to shake and not idle perfect all the time. Ive noticed it seems to do it more frequently in hot weather. I also noticed if it is idling with the AC compressor on, then i cut the AC off completely, then the engine idles down a bit (b/c it isnt powering the AC system) and it seems to bump or knock a lil bit more frequently than with the AC on. I can cut the AC back on and it idles like glass, then cut the AC off and it with kinda bump and falter every 10 seconds or so. Like i said again in hot weather. nothing major, just enough to feel at your feet and hear with your ear. It is not large enough for the vacuum on my boost gauge to move around at all. If it just does it at idle id say its somewhat normal at least in my experience (which is rather limited). 

Id also recommend installing a boost gauge just so you can see if your engine is running consistently in vacuum and under boost. I had a seal in a part go bad at one point (cant recall what the part was). But the engine would falter much worse and i could see a loss in vacuum at idle of about 5-7mm of Hg. Once or twice it was bad enough that the engine almost cut out. Eventually the check engine light came on with a fault code saying something like "minor air leak detected in intake system". The dealership replaced defective part and never had any issues since with that since.

In regards to your question of what indicates a failing cam follower, I have had a low fuel rail pressure code thrown several times under stg 1 APR software. The car went into limp mode for 30 seconds one day on the highway in 6th gear at WOT, it went from 18 psi down to 20mmHG of vacuum. I gave the car WOT and it would only got up to 6 or 7 mmHg of vacuum for that 30 or so seconds it was in limp mode. Then it kicked out of limp mode and would boost back up to 18 psi. This was on a pretty hot day out as well, it had a low fuel rail pressure code thrown. The car has not gone into limp mode since then, I am thinking the temp drop outside may have helped (since it is no longer summer). The only other thing i have noticed, is that sometimes in the top of 4th gear at WOT (5,500-6,000rpm) the car will kinda falter or not pull as hard for a second. I will look down at my gauge and the boost with drop down to 4 or 5 psi for a few seconds when it should be at least 8-9psi at that rpm. Im not sure if that is a sign of low fuel pressure. But seems possible. 

Anyway I would start by making sure you have a clean air filter in your car, make sure the fuel filter was changed at 40K, maybe change your spark plugs (go one heat range colder if you are running stg 1 software). Also see if your car is applicable for the coil pack recall that VWoA sent me in the mail (the dealership replaced all 4 of my coil packs free of charge, without any signs of problems with the coil packs). The replacement of the coil packs made no noticeable change in the car.

Sorry for the length of the post, i hope this info is helpful. Any other input is welcome.


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## StuMacLean (Aug 9, 2003)

DeeeGli,

There's really no good way of diagnosing the HPFP (high pressure fuel pump) follower issue besides a tear down and visual inspection. Well, tear down is probably too strong of a word, but you get the idea. I'd strongly recommend pulling yours in the near future, and most likely replacing. Lots of info on that out there, just use a few searches. 

The ticking noise that sounds like a TDI is our kick ass FSI fuel system. It operates "like a diesel" and simply sounds like one too. Nothing to worry about. 

The lumpy idle is indeed most likely misfires. If you look at the right measuring block (someone else help me out on the number) on Vag-Com, you can literally sit and watch as Vag-Com counts the misfires while the engine is at idle. This is something I've seen on other VAG motors too (2.7T mainly), and not really a concern of mine. I suspect it's something inherent with the VAG coil packs being wonky. I personally keep a spare coil pack in the trunk.

However, I'd respectfully request that we keep this thread to the subject at hand. Scientific (as much as we can be under the circumstances) analysis of the HPFP issue.


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## deeeGLI (Mar 1, 2006)

StuMacLean said:


> DeeeGli,
> However, I'd respectfully request that we keep this thread to the subject at hand. Scientific (as much as we can be under the circumstances) analysis of the HPFP issue.



Thanks for the input,and sticking to the subject is not an issue.
I've been on here for a few years,didn't want to start another useless thread.:thumbup:
Will be checking my follower soon.Thanks


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## StuMacLean (Aug 9, 2003)

Reviving this thread for another update. At 94k miles I changed my follower for the third time. This follower was in my motor from 75k to 94k all APR stage 1. 

Here's a picture of the follower:









As you can see the patch of worn away DLC is smaller than the previous followers (fewer miles). 

I measured the thickness of the follower again, and as you would expect it had lost slightly less material: 









In case anyone was going to crunch the numbers on my study thus far I'll save you the trouble. Slow day at the office:









Of course this isn't a perfect study. I was running a bone stock car for the first follower (50k). Then I went APR stage 1. So, the overall data trend may actually be a little more steep, but probably nothing dramatic. 

I'm thinking that 15k miles is about where I want to be changing the follower. This is sort of a drag because it's just that much more often but it's much less of a drag than letting the follower explode and send hardened steel through my whole engine......

One point worth noting is that I have only taken off about .0005in of material on this most recent follower. It is already through the DLC in some areas. That tells me that the DLC is only a few ten thousandths thick. That's not to be unexpected, but interesting to see it confirmed with hard data. 

Anyways, chime in on this if you feel inclined. :beer:


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## 87socorro (Oct 30, 2011)

whats good i have a question how do i know if i have cam A or cam B?


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## XM_Rocks (Jan 29, 2005)

87socorro said:


> whats good i have a question how do i know if i have cam A or cam B?


Checking A or B cam.


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## low_passat (Sep 11, 2010)

StuMacLean said:


> One point worth noting is that I have only taken off about .0005in of material on this most recent follower. It is already through the DLC in some areas. That tells me that the DLC is only a few ten thousandths thick. That's not to be unexpected, but interesting to see it confirmed with hard data.
> 
> Anyways, chime in on this if you feel inclined. :beer:


The thickness of the DLC is much less in reality, typically 0.5 - 3 μm (.00002/.0001"). What you're measuring is the Flatness of the cam follower face. Just a guess, but the manufacturing tolerance is probably .0001/.0002" flatness, so you are seeing some wear of the steel.

Here's a link to a Oerlikon Balzers PDF showing DLC thickness
http://www.oerlikon.com/ecomaXL/get_blob.php?name=HQ020EN_1010&download=1


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## bificus99 (Aug 2, 2008)

So if end users like StuMacLean can come up with data like this WTF are the VW Audi engineers doing for a maintenance schedule and waiting til the cam and pump destroy themselves?
Thanks StuMacLean!


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## XM_Rocks (Jan 29, 2005)

bificus99 said:


> So if end users like StuMacLean can come up with data like this WTF are the VW Audi engineers doing for a maintenance schedule and waiting til the cam and pump destroy themselves?
> Thanks StuMacLean!


I have been screaming this for years.

This is a ticking time bomb for VW.

The warranty extension does not fix the root of the issue.

Back in 2007 when issues started to arise all they would have had to do is issue a check/replace interval in an amended service manual. Instead they stuck their head in the sand.

Every FSI I see in a parking lot with the owner near I always tell them to Google "Cam Follower FSI" and to check and replace... they probably think I am nuts. :laugh:


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## dmorrow (Jun 9, 2000)

bificus99 said:


> So if end users like StuMacLean can come up with data like this WTF are the VW Audi engineers doing for a maintenance schedule and waiting til the cam and pump destroy themselves?
> Thanks StuMacLean!


I'm sure VW Audi engineers have piles of data on this issue by this point. Normal course of action for most businesses is to give this information to upper management and they make a business decion on what to do. Regardless of what Engineering thinks they don't just come out with new maintenace or warranty procedures that get sent to the public.

VW/Audi made a decision that their current path is the correct one. I am sure they know far more about the failure rates and wear rates than any of us do.


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## StuMacLean (Aug 9, 2003)

Dmorrow hit the nail on the head. It's just like fight club:

"Take the number of vehicles in the field "A." Multiply it by the probable rate of failure "B." Then multiply the result by the average out of court settlement "C." A time B times C equals "X." If X is less than the cost of a recall we don't do one." 

Although in our case it's motors exploding, not passengers (thank goodness). 

In the long run it sure seems like VW would have been better off financially by implementing a customer paid for scheduled maintenance plan and skipping out on the 120k extended warranty. However implementing that maintenance plan may have brought more attention to the reliability issue and damaged the company reputation for reliability and cost of ownership (no pot shots please). It would cost about two to three hundred dollars to have a follower replaced by a dealer, and that replacement would be almost annual for most cars (to keep the intervals on the safe side). That sort of fixed maintenance cost scares away a lot of potential buyers even on the used market. 

Speaking as an engineer, the amount and quality of data I'm gathering is quite insignificant in comparison to what an engineer would need to have in order to make an informed decision about how to remedy the problem with the fuel pump follower design.


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## bificus99 (Aug 2, 2008)

StuMacLean said:


> Dmorrow hit the nail on the head. It's just like fight club:
> 
> "Take the number of vehicles in the field "A." Multiply it by the probable rate of failure "B." Then multiply the result by the average out of court settlement "C." A time B times C equals "X." If X is less than the cost of a recall we don't do one."
> 
> ...


This is what I expect engineering vs marketing and management.


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## bificus99 (Aug 2, 2008)

XM_Rocks said:


> I have been screaming this for years.
> 
> This is a ticking time bomb for VW.
> 
> ...


That wasnt sand!


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