# Question: 2.8 30v loose timing belt tensioner / damper failure? AHA



## markcm (Jun 19, 2009)

Hi folks,

I am fairly familiar with these engines but this has me stumped. The car is our 99 Audi A6 AHA 2.8 30 valve.

HISTORY: In the past I did a Timing belt replacement and used inferior parts (listed as OEM "quality"), the timing belt tensioner/damper collapsed within about a week. Fortunately my wife (it's her car) heard the belt slapping around, I found the damper was totally collapsed and we replaced it before skipping any teeth. Since the part was from a semi reputable seller (I think it was FCP groton but dont really recall now) and it was called "OEM", I installed the replacement they sent which arrived in a thin yellow straight from china box with no markings on the casting, guess what, same thing within a week but again no major damage done. At this point I went to a local euro shop and got an NTN (they charged me $170, ouch!!!).

It has been over a year and now my wife heard the slapping again; I heard it as well. Knowing this sound, we parked the car asap, I pulled the TB cover and sure enough the belt was super loose, I effortlessly deflected the belt well over an inch. The car was in our garage so I crossed my fingers and started the car to move it to my shop where I could tear in to it. I heard the belt slapping around but no issues arose; I put the car on ramps in the shop. 

Here is the problem, I pulled the bumper and pulled the core forward, pulled the TB covers and to my surprise the belt is completely tight. What the heck? I cant believe a damper could or would collapse and then some how regain it's spring force.

Does anyone have any insight as to how the belt could have been so loose and then after starting the car once, the belt is now taunt?

I'm presuming I should just replace the tensioner/damper right now; the belt, water pump, cam seals... were all done with in the past 12 months.


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## MattySull (May 17, 2006)

I hate sporadic problems like this that correct themselves only to show their ugly face 2 weeks later.

To be honest, I've heard of a ton of "OEM" dampeners for the AHA engine being fault. It has gotten to the point that I couldn't even tell you where to look for a decent one. Anyway, it is not out of the realm of possibility that a pneumatic device hangs up and then starts working correctly. I would replace it though.


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## markcm (Jun 19, 2009)

Agreed, what a bummer that even OEM parts aren't reliable in such a critical application.

I decided to go ahead and replace it even though I've started the car multiple times and watched the timing belt, not once losing tension. On the other hand, I can see where grime has been rubbed off the water pump where the timing belt passes it which could only happen in a loose belt situation; when it's tight there is a good inch plus clearance.

I shopped around, I like RockAuto, Amazon, and Arizona Autohaus but in this case, FCP Euro had sent me some fairly personal content regarding improvements they were making and response to a survey I'd filled out; I was fairly impressed with that and also found they had the lowest price on the internet ($52 shipped) for an NTN dampner/tensioner which as far as I know is as close to OEM as it gets. Unfortunately, the one in there now is also NTN with about 30k on it.


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## markcm (Jun 19, 2009)

I put the new NTN tensioner/damper on tonight, put the car back together, and when I started it, it was whirring loudly. I stopped the engine and found the belt was super tight, I could "twang it". I started it several times and drove it around the block, then rechecked, it was quite but still very tight "twang".

When I had it apart, the tensioner roller and it's corresponding tensioner lever seemed to move freely but now I'm thinking I should have replaced them as well since I didnt know what the root cause was. when I put the tensioner in, there were several millimeters of slack, as I recall there should be about 7mm between the compressed piston of the tensioner and the lever it presses on; anyrate, I didn't adjust the roller as it seemed to be correct. I pulled the pin on the new damper and all seemed ok until I started the car and the belt tightened up.

So I suppose I'll take it apart again and replace the roller and lever this time.

ARGh!:banghead:


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## markcm (Jun 19, 2009)

Ok, I pulled the core support forward again and stripped it down to the tensioner. It does seem like like the roller bearing may be worn and not rotating freely as it should; I should have just replaced it with the tensioner (shame on me). So, I ordered a new lever arm and roller from FCP, when the arrived to my surpise the Timing belt Tensioner Bearing roller was GMB brand, I could have sworn I ordered NTN , So I looked up my order and sure enough I accidentally ordered a GMB brand. When I did a search, I notice that the GMB and NTN show up right next to each other, I obviously accidentally clicked the wrong one .

Well, I don't know much about GMB but the limited reviews I did find on google don't sound all that positive; the NTN is only $2 more so I sent the GMB back and ordered the NTN. 

Fortunately I have an "extra" 2004 A4 avant project car that is drivable while this car (my wife's A6 Avant) is down.


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## JohnStamos (Feb 3, 2010)

The tensioner lever likes to get gummed up from oil leaks at the cam chain tensioner gaskets, and it causes the lever to get hung up, especially in the cold. 

Engine warms up, and the belt gets tight again as the lever is able to move. This is worsened by aging tensioners. 



Pull apart and clean the tensioner lever, there will be a bushing inside, with a sleeve it rides on, and lube it with a low viscosity marine grease, or replace it entirely, making sure it is lubricated well.


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## markcm (Jun 19, 2009)

Thanks for the tips.

I have new NTN Tensioner, lever, and roller bearing (bearing yet to arrive). I Will install all 3 this time.


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