TwoTT

Folks, long time TT owner, and occasional lurker here. Bear with me for a minute...

I've just read up on the Dealer Timing Belt Inspection Fiasco. Not too surprising.

Of course, I just got a call from my Dealer letting me know that the belt was cracking on my 109k 2000 MkI. Interestingly enough, the same Dealer did the belt, pump, etc., at 72k miles, but this service advisor wasn't able to dig up the record. But, I was, of course able to.

Now, barring the obvious explanation of the Dealer just wanting to change the belt to cover its butt, is there any collective evidence of mechanical reasons why a second timing belt would need to be replaced after three years and about 35k miles?

I just scanned through the DIY belt procedure, so, I know I can do it myself. But, I own 3 Porsche 928s and have just not-quite enough wrench time to keep them in top condition. I've done the timing belt on 928s dozens of times, so I know what goes on with them. In particular, some of the components have different wear rates than others and need to be replaced with every-other belt replacement (more-or-less, depending upon wear etc.) Specifically, the aluminum cam sprockets and oil pump sprockets need to be replaced once the 928 gets into the 90-110k mile range along with some other odds and ends with which I won't bore you.

SO.... on to my question about the TT:

Is there any evidence of timing belt system components other than the water pump, belt, roller, and damper needing replacement at the 100k+ mile mark? Like the cam sprocket or crank sprocket? Are there any other items subject to wear in the long term in the system? Bushings, bolts, yada, yada?

MCPaudiTT - DEFCON 1

Either give in and change your belt now, or FIGHT IT tooth-and-nail, with your evidence in hand. Either way you go, ask the dealer to CLERALY show you where the belt is cracked ON YOUR CAR. He will likely come back with something like "oh, that was the other TT we were looking at, and yours is fine, sorry about the mix up" or something like that.

With regards to skills, you have the needed skills to do the job, it is a pain, but not difficult. If you have done 928 belts, you know the "general" procedure, just follow the guides and you should be fine.

That said, you should be able to go another 20k miles and 2 years with no issue.

TTschwing

Based on owner reports of the "inspection" here. Sometimes it's NEVER looked at and this is reported to the owner.
You might want to take a look yourself.

What could cause cracking? Poor quality replacement belt, Heat, other envoirnmental factors. Experience here does not show a prevalence toward cracking if the 60K replacement point is adhered to. Water Pump, Timing belt, and Tensioner are the common replacement items with nothing normally needed in the interim between changes.

TwoTT

... if they are trying to pull a fast one on me I'm going to have a nice chat with Service Manager with whom I have had good relationship for a very long time.

I can list all the other likely causes in order of probability:
- Dealership CYA
- Tech didn't actually replace the parts listed on the 72k invoice.
- Tech screwed up
- Defective parts
- Audi Engineering isn't as good as they think it is.

I am just interested in if other parts in the timing belt system - those that are not part of the standard replacement set - are known to warrant replacement when the mileage gets into the triple digits. That kind of information doesn't always filter all the way down to where it needs to.

TwoTT

... but wanted to get my fecal matter all accreted before the trip.

MCPaudiTT - DEFCON 1

is, in fact, these items that fail in almost all the "timing belt failure" instances. These parts seize due to failure, rip off the teeth of the timing belt, and the belt takes all the blame for the failure (it is, from the outside, the "obvious" cause of the damage, but is in fact NOT the root cause). I don't think you will find even one case on this board where a belt failed, but both the water pump and tensioner were in perfect order. In addition, you will find many cases where the belt was changed proactively, and severe damage to the water pump and/or tensioner were apparent - and failure of those components was imminent.

TwoTT

... its always something that was not done or was overlooked. Always. (Well, sometimes premature belt system wear is due to a bad out-of-the-box water pump...)

On 928s the simplest error is not replacing two bushings that keep the tensioner roller carrier from vibrating. On 100k+ mile 928s the oil pump sprocket and cam sprocket coatings gets worn off to the point that the aluminum sprocket teeth get sharp and start nibbling on the belt.

That's why I'm particularly interested in the TT's sprockets. Are they coated aluminum or steel?