Got my first Audi this January, 1999 A4 1.8t FWD. Car only has 52k miles. After a lot of reading about these cars I decided to change the timing belt and tensioner. Got the parts from ECS, changed all belts, water pump and thermostat while I was in there. Before doing this work I noticed this noise once, but since it has gotten much worse. Rattling/clanking noise only at idle or revving engine while sitting still, don't notice it when car is moving. Saw some other posts describing this as a cam tensioner problem. However I thought I had found the cause as being the A/C belt tensioner, so I replaced it and the noise went away by about 90 percent. That only lasted about a week and now the noise is almost as loud as before. Just wondering if anyone else has had issues with this part. Maybe this weekend I will pull off the A/C belt to see if it goes away completely. Oh and by the way this noise does not affect how the car drives, I can't believe how quick this car is with only 150 horsepower.

Thanks for any help... Don

 

when you turn off the A/C does the sound go away?

 

cam tensioner--- about a $700 on parts

 

I've had the same problem, although I just had my timing belt and all that jazz done. Its been off and on though so I haven't really diagnosed the problem yet. Its off more times than its on, but when I'm on the throttle or at idle it squeaks. With clutch engaged, nothing. **** that **** about 700 for a cam tensioner.

 

The noise is worse with the A/C off. The first time I noticed that the A/C had an effect I had just started the car and the noise was pretty bad, when I turned the A/C on it instantly went away, turned the A/C off and it instantly came back. I thought maybe I did not tighten something after the timing belt change and while checking for something loose noticed that there was some play in the A/C tensioner roller. I could wiggle it enough that it made a clicking sound. So I changed it and like I said it almost got rid of the noise, if you were not paying attention you would not notice it, but it has been gradually getting worse. It is still not as bad as before but getting there. It is also much worse when the car is cold, after driving a few minutes it is still there but much quieter.

 

Just a follow up, I looked at the car this past weekend and it turns out the noise was my fault all along. The four 6mm hex bolts that hold the pulley attached to the crank shaft were not fully tightened causing the noise. I know exactly how it happened now that I fixed it. After I put it back on and tightened it up I realized I forgot to reinstall the lower timing belt cover, so it had to be pulled off again. Somehow when I put it on the second time I did not get them fully tight. Luckily I was able to get to them from underneath the car without pulling the front end off again.