84 Audi 4000S 1.8 litre, 5 speed. All belts good (just changed) but getting a sound a bit like that which comes from a too-loose alternator belt.However more of a "warble" than a screech and seems to have no relationship to engine speed or electrical load. Fairly constant when moving but when at complete stop it abates totally. I have also noticed that depressing clutch seems to alter volume a bit (actually gets a little louder when clutch is being depressed) One other quirk, seems to quite a bit under acceleration load and at interstate cruising speed I can barely make it out but it seems to almost "cycle" off and on. Water pump is new as is timing belt.My son's car and he reports that the noise has been irregularly occurring for several months but has become fairly "steady".
Clutch bearing maybe??? Maybe pilot bearing ? Maybe clutch release bearing??? other ideas?? thanks.

Thanks for suggestion. May be but timing belt was replaced recently and the noise was unaffected. New water pump insatalled at same time. Fact that noise changes a bit in response to clutch manipulation makes me think the problem may lie there.
One other thing that occcurred to me that I will check tomorrow is the tension on the power steering belt. However, I doubt that is culprit as again, the noise changes a bit when clutch is worked.

It happens on turbo I5s and cause major mixture issues with them. Not sure its a problem on the N/A I5s. Try pinching off the biggest PCV hose on the motor. If the sound lessens, then its a crank seal.
HTH

Never would have occurred to me to consider that. Will give it a shot along with other checks . Thanks.

Just thought I would let everyone know. Turned out to be clutch. I was able to adjust the free play and make it go away. Go figure.