jrk2717

I have a 2009 A4 (B8) with 110k miles. Lately I've noticed a noise coming from the engine that has progressively gotten worse. The sound is loudest when I start the car (hot/cold) and continues to rattle/growl at idle and while driving.

I looked under the hood and noticed something rattling/loose near the belts. Not really sure what this is and if it's something I can fix myself. I've looked into serpentine tensioners going bad but not sure if that's it.

(Video of noise at start, next video noise at normal idle.)



Any help would be greatly appreciated.

Thank you!

A-Car

Just came across... was it the serpentine / accessory belt tensioner (?)

jrk2717

It was actually the alternator clutch. Could have just replaced the clutch itself but I bought a new alternator and drive belt instead. Problem seems to have disappeared.

Azazzell

Just saw this post also. For others that may want to know you can tell it's the alt. by all of that red/brown clutch dust on the front. She's toast. Glad you got it fixed.