faint buzz or whistling sound

[jefla]

I've a 2000 Boxster w/ 45k mi, that's making an intermittent low-pitched monotone hum or buzzing sound that I need to ID.

At first it was very faint, sounding like a bad wheel bearing humming. It would come and go and did not change tone, etc w/ changes in engine/vehicle speed. Now its louder although still faint -- and still sounds like bad wheel bearings I've heard. Porsche mechanic said that's not it, but I'm not convinced he heard it. Anyhow, it sounds like it could be coming from the front or right side of the car, which has me thinking i'ts a radiator fan. But, it could be coming from the right air vent i.e., engine compartment. I can't get it to happen when the car is parked, of course. (And I'm deaf in my left ear so the **** sound could be coming from anyplace ....). No helpful CEL codes.

Many Thanks

[jefla]

Oh man, one of you must have an opinion on this -- noise is driving me nuts. New info: it seems lifting off the accelerater will cause the sound to stop. Applying brakes or the clutch makes no difference.

[RFM]

Hi

Is the noise only present when the car is in motion or can you hear it parked with the engine running ?

[jefla]

Only when moving. Not speed dependent and tone does not change w/ speed.

[RFM]

Lifting off the accelerator will cause the sound to stop - i think that it is more engine related than chassis related, check the front engine mount, they go's bad. The silent bloc have to be straight in the middle of the mount. An other possibility is the aircon. compressor, they are noisy when the R134a ( gas ) is to low. You need 0,850 Kg. the noise starts approx. at 0,450 Kg while the aircon. will work normally.

Success.