I already know that the clutch on the compressor is bad, but i've never heard this horrendous sound before. Sounds like its grinding or something. Mostly at idle, kinda comes and goes. J/w if anyone else had this experience....

 

Yeah, when the AC clutch went bad. I've had one get stuck in the engaged mode, and another lock up and not want to turn (that was obviously worse).

 

I have had exactly what you are describing happen to me recently... in fact, I just posted about it on another board!

http://www.ws6zxr.com/showthread.php?s=&threadid=21984

I dunno what mine is either, but I was thinking the compressor is going, or I'm low in R134a and oil.