hello all,
recently posted a video here about a strange noise im getting in my 2002 a4 1.8 amb,
only happens when car is in gear- just as clutch is released, a sort of rattle humming sound.
anyways finally traced the noise to the tensioner on the v belt,replaced tensioner and problem still persisits.
you can actually see the tensioner flutter as the clutch is released and engine comes underload,if i hold the tensioner with a visegrips the noise goes away,it only last for the innitial few seconds as the car goes into gear then disappears.
my mechanic who i trust for years is also dumbfounded by this, we put two tensioners in- first a dayco and then a dealership one, but the noise is still present.

he believes for some reason the v belt isnt getting proper tension and is actually slacking causing the flutte/r vibration for those few seconds, maybe an internal fault??

sorry for long post, hope someone can finally chime in.

 

Are you sure the engine is not misfirig as it coes under load, or maybe the clutch is chattering?

 

No misfire, no clutch problem, like i said if i clamp the tensioner and put force on it the noise stops. Ill try an video again and post