Okay, here is the deal, I have replaced the ac compressor twice. I put a new one in about a month ago and noticed that at higher RPMs it would whine (high pitched as if the engine was turbo charged). I took it to a couple of places to have them check it out. One said the compressor was failing another said everything checked out fine. (The pressures were fine and the ac was pretty cold). So I called the manufacture and told them. They were hesitant but sent me a replacement. After I installed the second one I still notice the whine almost immediately. The whine only happens when the compressor is engaged.

So now I am wondering if it actually the compressor or possibly the idler pulley. I have read a few places where the idler pulley may make noise with the "extra" load when the compressor is engaged.

Thoughts????

 

can be a water pump too i guess... best bet use stetoscope (sp?) to find out which bearings are shot its available in most of autozones, pepboys stores