maaliish

When the car is cold and has not been driven for a while (8-10hr) I get this weird buzzing sound coming from the top of the engine close to the firewall. The sound seems to change pitch when throttle is applied and is almost non existant when the car warms up and the rpms are at normal idle, but raise the rpm and you can hear it. When the car is cold, the sound is very vivid.
The sound disapears when the car is fully warmed up (after about 15-30 minutes of driving) and the engine is very very quite than.
The sound seems to appear more and more often so I am getting worried.

It does not click like a valve, just bzzzzzzz going higher in pitch with RPM.

I have a feeling it is something in the intake, it almost seems like a loose nut jumping allover the intake of the engine.

Any sugestions, comments?

Thanks.

audifirst

I am getting the samething every morning or after the car is cool down... to me it sounds like something is loose in the front of the car. maybe I am wrong by it sort of comes from area in the front where the belt drives all the poleys, could be a poley or bearing on one of the poleys.. I have called audi dealer and they ask me to bring the car.. I've got no time in the morning for visitation...

maaliish

Mine comes from the back near the firewall that separates the batt and ecu from engine compartment.

audifirst

I am going to check it again in the morning, maybe you are right, the sound could came from any other places.. it will be nice to hear from other person who can confirm their findings...