Recently, I started driving a 97 Cavalier with 101,000 miles that had been, for the most part, parked for a year. Right away I noticed a constant metallic friction sound when the engine is running. I hate to call it a grinding sound as it doesn’t sound that loud, but that could be another way to possibly describe it. It does it whether the car is moving or not. I have listened closely under the hood and I think it may be coming from the alternator. Could there be a bearing going bad in the alternator? Or might it be something else turning with the belt, like the AC compressor? I do not remember it making teh sound before being parked last summer, so could something have happened during the last year to cause this?
it could very well be the alt. or the belt tenioner.
If the noise is coming from around the alternator I would suspect that the bearings of this are failing.
If you have a long screw driver, place the tip on the laternator and put you ear on the end of the handle, if it is the alternator you will clearly hear it then.