Hi all,

So I picked up my 2006 2.0T A4 two and a half weeks ago from my local dealer. The car was certified by Audi and is also still under warranty. About a week after having the car home, I noticed a squeal coming from under the hood on cold starts. I figured it was a serpentine belt and/or tensioner and took it to the dealer to have them replace it. They did so at no charge and sent me home.

The next day the squeal was back and I was irritated. I went back to the dealer and they kept the car for 8 hours before replacing the crankcase valve. The tech said is was whistling and that was the noise I was hearing.

Two days later and the squeal is back. Only now, I don't just hear it on start-up - the damn thing squeals while I'm driving. The noise changes slightly with engine revolutions, but not much. It now happens regardless of engine or ambient temperature.

I've booked another appointment with the dealer, but frankly I don't trust them at all.

I'm going to get out my automotive stethoscope and try to find the problem myself before I take it in, any ideas where I should start looking?

Thanks in advance.