Alternator clutch
 

Ever since I got it my 2.8 has sometimes made odd noises at low revs when cold with some slight sensation of it being passed back through the steering wheel. The PO thought it was the water pump, then the power steering pump. It is true the worst of the noise does seem to come from the PS pump.

I’ve been ignoring it as I was fairly sure I knew the true cause having encountered it before on my sons 1.9TDI A4.

Confirmed today that it’s the over-run clutch on the alternator, which is seized. I have no idea what VAG design quirk makes these needed even on a smooth running V6 or V8..... it is certainly true that the failure produces much more violent symptoms on a diesel 4 pot.

So I need to source a new one. I already own the special tool..... hoping it can be done in situ......

Pretty sure the one on the wife’s TT is also borked. I’m ignoring that as it is even nastier to work on and the symptoms very subtle.

Nick

Oddly enough, the V8 doesn't have the clutch - only the V6. Its basically the same alternator with a different rear cover so I guess its to do with harmonics that the V8 doesn't have.