JPQuattro

So my new to me as of today 00 S4 has developed a whining/bearing rattle from the engine bay on decelaration. I suspect the serp belt tensioner as there is no noise upon accelaration or in nutrual.

I am going to remove the serp belt in the next few days to isolate but have not see a bearing noise only upon decelaration, it comes from the front & resonates towards the cabin area.

Ive read a bunch of posts about the pump bearings, alt, tensioner causing the kinds of issues just am really curious if anyone has seen a decelaration issue, hoping not a trans or transfer case bearing.

TIA

Rory

How do you know it's not a wheel bearing? These noises can be difficult to locate accurately.

JPQuattro

Def not a wheel bearing, done a few of those. Its more of a rattle/bearing noise. It vibrates thru the engine block to drivetrain. Ive only read 2 instances of this similar noise.

Going to check the drive shaft u-joint & bearing. Also I hear the wastegate flapper can do this if actuator is going bad. Anyone else have this issue?