I have a 98.5 2.8QM which has roughly 4300 miles on the engine. The other day as I was driving I heard a distinct ringing noise pierce through the radio. I turned off the radio and tried to isolate the problem. It seems to occur at a distinct point of acceleration or de-acceleration between 2000 and 3000 rpm in any gear. It also seems more pronounced on wet roads. If you work the accelerator just right you can really make it sing (I'm sure dogs around the Bay Area hate me by now). I wish I could say I've had the dream car w/o problems but this one surely takes the cake. Any ideas or suggestions? I've found that my service department needs a lot help on diagnosing problems. Thanks for saving my sanity!

Hmm, does the pitch of the "ringing" vary with the RPMs? <p>Sounds like it could be a short-circuit, or a pinched wire that's creating the "ringing" sound... If you can definitely repeat the noise, take it to your dealer for warranty service, and give them an exact description of how to reproduce it...<p>Electrical problems are a real pain to diagnose, it once took my dealer 3-1/2 days to figure out what was causing my front passenger-side speaker to die on me (pinched wire in door panel)...<p>-Phil

Thanks for the reply but I should have described the symptom a bit better. The noise is not related to the radio but seems to emanate from the outside right rear of the car. I realize that totally changes the tone of the problem (I know - bad pun) but any insight is appreciated.<p>Thanks!

Couple of ideas:<p>1) Loose exhaust system heat shield. Had a weld point break loose on the heat shield around the sdownpipe on my old Coupe Quattro - induced a very high-pitched metallic rattling under certain engie speeds (esp. during deceleration).<p>2) Air leak around doors/windows/trunk or a trim piece sticking out. This could be causing a hum/ringing effect as air rushes out leak or around trim. On my old Honda Accord there was a small gap between the windshield and the trim surround of a perfect size to create a wind whistle at speed that drove me nuts. faster you went, worse it got.<p>3) Driveshaft (front-to-rear or ones to wheels) rubbing someplace. I had a muffler hanger break on the old Coupe Quattro, caused a mild squeal at speed as muffler rubbed on driveshaft. Also check for brake heat shield rubbing rotor.<p>These noise problems are a real PITA to isolate. If it is car-speed sensitive, would concentrate on body mouldings or air leak; if it is engine speed sensitive, check the exhaust system.<br>

I had my dealer check it out. It is only detectable with the radio off and definitely more so in the right rear seat. <p>The dealer looked into it and told me that it was the Quattro system. They said that "you do hear the Quattro occasionally, that is normal." <p>If you find out anything different, I would be interested in knowing. I have a 99 A4 2.8QTip, with Sport Pkg (only things I think my be relevant to sound).<p>Kirk