So here is a new one, my passenger foot well is screeching at me.

When I hit about 3500 RPM a screech develops and contnues until I drop back below 35000 rpm

Does it with AC on or off.
Does it at any or no fan speed .
Does it in drive and nuetral.

My thoughts are the AC compressor is having issues, or that the serpentine belt is slipping at that speed range and the sound is coming through the foot well.

Any other thoughts or tests?

 

I would suspect the serpentine belt. Take a look at it and see if the grooves are worn or glazed. If they are you need to replace it. While you have the belt off clean your pullies so you don't transfer dirt/glaze from them onto your new belt. Also check the belt tensioner for proper operation. A worn bearing in a belt tensioner will squeel also.

 

Just because you'll have the belt off, check the PS fluid too.

 

Ha Ha, I do that every six months, it never leaks out anywhere but seems to get low at random.