Gary Knox

My '07 A8 has 90+K miles on it, and I'm going to change the serpentine belt soon. I suspect I should also change the tensioner pulley - is that correct?

What about the idler pulley that is up above the tensioner pulley. Should that be changed as well?

THANKS for your counsel.

Mike141

I just changed my belt, checked the pulleys and they seemed fine so I decided to leave them be. I guess it's good preventative maintenance though. On my last A8 the tensioner broke on my way to work but only after the bearings were making noise for like a month. It was my fault, I shoulda replaced it when the bearings started rattling.

richard-tx

It is a good idea to change the idlers as well. Only someone with experience handling bearings can tell if a bearing is starting to fail or is noisy. When my son changed his idlers, the drop in engine noise when idling was dramatic and significant. In the end, the noisiest part of the engine was the pulsing of the injectors. When my car comes due for it's next belt change, the fans will also be replaced.