THE Timing Chain Tensioner Failure Thread

[A4x]

Ok, so I was able to dig up my paperwork from my STG II Oil Consumption job...work was done at 62k miles in May 2014. At that time, they replaced the chain tensioner with revision K. Fast forward 47k miles, self destruction. Here is the timing info:

https://flic.kr/p/YucyxG

https://flic.kr/p/CsLrYQ

For a "lifetime" part, it definitely should not fail 47k miles after being brand new. There must have been some other issue which was not addressed at that time which worsened over time (i.e. chain was in rough shape and should have but wasn't replaced) or the new part itself was faulty. But hell...lets be honest...there could have been several different things going on...but hopefully this will help in my pursuit of getting this paid for by either the dealer or AoA...

Will keep thread updated...

Is this the first evidence we have of the revision K tensioner failing? I thought that this was the updated part that shouldn't fail. I recently paid a decent amount of money to have the revision K put in my car @ 75000 miles!!

[B8_Dude97]

Is this the first evidence we have of the revision K tensioner failing? I thought that this was the updated part that shouldn't fail. I recently paid a decent amount of money to have the revision K put in my car @ 75000 miles!!

I wouldn't call this evidence. Tech didn't check chain stretch. It also makes no mention of replacing the guides/rails. That was a piss poor bandaid job to be frank. Op should've requested guides and new chain due to the twnsioner fully collapsing under load.

If you do a tensioner swap you should change the chain if your close to 100k the guides should also be replaced while your in there


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[craigiemac412]

I wouldn't call this evidence. Tech didn't check chain stretch. It also makes no mention of replacing the guides/rails. That was a piss poor bandaid job to be frank. Op should've requested guides and new chain due to the twnsioner fully collapsing under load.

If you do a tensioner swap you should change the chain if your close to 100k the guides should also be replaced while your in there


Sent from my iPhone using Audizine

Knowing what I know now, I would agree that this was poorly handled by the dealer doing the original work. I was not advised with regards to anything timing (and did not know anything about it then either -- that work was done over 3 years ago). I would have paid the extra few hundred dollars at that time to do it if I knew about the issue or was advised about the situation...but then again that was only at 62k (not really close to 100k) miles and there likely were not a lot of chain tensioner failures back then like there are now.

Here's my concern: what happens when you have an owner who is not very technically inclined and would have no idea about engine timing or failure rates about a poorly designed part? I would argue that the majority of A4 (and 2.0T in general, Audi or VW) owners would fall into this category. That would not be true to a lot of people on this forum, given the nature of what this forum is, but in general that is the case. And even still...there are plenty of folks on this forum who know only basics and some even don't know anything about engines and are only concerned with aesthetic changes (i.e. wheels, suspension, etc.). An owner can only make as educated of a decision as they know facts, whether through self discovery or being presented to them (i.e. Service Advisor).

With that said, how many folks are blindly getting bent over because they simply don't know any better? My guess...A LOT. That's my concern.

[audrobotic]

Knowing what I know now, I would agree that this was poorly handled by the dealer doing the original work. I was not advised with regards to anything timing (and did not know anything about it then either -- that work was done over 3 years ago). I would have paid the extra few hundred dollars at that time to do it if I knew about the issue or was advised about the situation...but then again that was only at 62k (not really close to 100k) miles and there likely were not a lot of chain tensioner failures back then like there are now.

Here's my concern: what happens when you have an owner who is not very technically inclined and would have no idea about engine timing or failure rates about a poorly designed part? I would argue that the majority of A4 (and 2.0T in general, Audi or VW) owners would fall into this category. That would not be true to a lot of people on this forum, given the nature of what this forum is, but in general that is the case. And even still...there are plenty of folks on this forum who know only basics and some even don't know anything about engines and are only concerned with aesthetic changes (i.e. wheels, suspension, etc.). An owner can only make as educated of a decision as they know facts, whether through self discovery or being presented to them (i.e. Service Advisor).

With that said, how many folks are blindly getting bent over because they simply don't know any better? My guess...A LOT. That's my concern.

I agree to all that. That’s why I’m like a broken record in saying to avoid the B8 (vs B8.5). People who havent done their research will see a “cheap” Audi and think “what could go wrong?”. And it’s more complicated than just the tensioner part.

The updated tensioner is a very different design. The original was meant to work off of oil pressure. Which when you have oil consumption issues is the worst setup you could have. Now when you have a B8.5 with no oil consumption issues, no tensioner dependent on oil pressure, you are in much better shape relability-wise. The B8 in the other hand is just a perfect storm of compounding issues.

[jfo]

I agree to all that. That’s why I’m like a broken record in saying to avoid the B8 (vs B8.5). People who havent done their research will see a “cheap” Audi and think “what could go wrong?”. And it’s more complicated than just the tensioner part.

The updated tensioner is a very different design. The original was meant to work off of oil pressure. Which when you have oil consumption issues is the worst setup you could have. Now when you have a B8.5 with no oil consumption issues, no tensioner dependent on oil pressure, you are in much better shape relability-wise. The B8 in the other hand is just a perfect storm of compounding issues.

I've seen parts listings that show the same tensioner is used on at least up to 2017 models, and they all use oil pressure. Where did you see it was different?

[audrobotic]

I've seen parts listings that show the same tensioner is used on at least up to 2017 models, and they all use oil pressure. Where did you see it was different?

Youre probably right. I’ll have to revist my sources. It’s likely a bit more nuanced. The current models probably use oil pressure but arent as prone to failure in that regard.

[jfo]

Youre probably right. I’ll have to revist my sources. It’s likely a bit more nuanced. The current models probably use oil pressure but arent as prone to failure in that regard.

They use oil pressure while the car is running. The piston is locked by the notches and retainer to keep it in place when the engine shuts down. The retainer on the old design was not robust and simply wore out, allowing the piston to retract and chain to slacken. The K version has been in place since sometime in late 2014 I believe, and is still current. Hopefully, this means it will last a long time!

[mtroxel]

I wouldn't call this evidence. Tech didn't check chain stretch. It also makes no mention of replacing the guides/rails.

I agree. I did this job last week. Updated to the K tensioner, but gee after all the hours it takes to get there, do the chain and guides too. I saw a tech friend of mine doing this job on another car. Tensioner was fine, but it was all the way out! Meaning the chain had stretched so far the tensioner was about to be useless, even though it was still healthy.

Here's a side by side of my 85,000 mile chain and the new, revised chain. Note the old one had stretched a bit, and also note the revised design to correct the stretch issue on this "lifetime" chain.

[jfo]

I agree. I did this job last week. Updated to the K tensioner, but gee after all the hours it takes to get there, do the chain and guides too. I saw a tech friend of mine doing this job on another car. Tensioner was fine, but it was all the way out! Meaning the chain had stretched so far the tensioner was about to be useless, even though it was still healthy.

Here's a side by side of my 85,000 mile chain and the new, revised chain. Note the old one had stretched a bit, and also note the revised design to correct the stretch issue on this "lifetime" chain.

Thanks for the pic. Your stretch looks quite small, which is good to see at 85K. How were the guides?

[mtroxel]

Thanks for the pic. Your stretch looks quite small, which is good to see at 85K. How were the guides?

Yea that stretch isn't bad for 85,000. And my guides were all brown, but almost no visible wear. Still, once you get in there, don't know why you wouldn't do it all. And I've seen much worse stretch on some others.

EDIT:

When I said the guides were OK, I was thinking of the cam chain guides. But I was about to put the cover on when I noticed this on the oil pump chain tensioner guide. This didn't have but a month or two left:

[jfo]

Yea that stretch isn't bad for 85,000. And my guides were all brown, but almost no visible wear. Still, once you get in there, don't know why you wouldn't do it all. And I've seen much worse stretch on some others.

EDIT:

When I said the guides were OK, I was thinking of the cam chain guides. But I was about to put the cover on when I noticed this on the oil pump chain tensioner guide. This didn't have but a month or two left:

I agree and would spend the $$ to change out these parts while in there. It's good to see reasonable or minimal wear at your mileage(exception noted) on those parts though. I'm only at about 55K miles and my chain looks good based on the extension I see on the tensioner. Looks like I'm good for a while longer before tearing it open. My dealer did the tensioner, upper guide and cam bridge as part of the stage 2 fix about 2 years ago. They did it on their own and I didn't notice until I looked at the parts list and asked them about it. Unlike many of the reports we see, there are some good, customer oriented dealers out there.