Bump to wake up an old thread with what I believe might be a similar problem (idler pulley noise)? Driving around town at speeds low enough where the wind/ exhaust noise are not too loud, I hear a high-pitched whining/grinding noise coming from the engine compartment. It is not the SC whine. When I increase the engine speed, the noise is even more pronounced. The car is my daily driver, so my ear instantly picked up the funky noise about a week ago. Strangely enough, I first heard the noise after rumbling from 40 to 0 mph over a rocky, offroad parking lot in front of the entrance to my base, leading me to think that the harsh vibrations combined with low pull from the crank pulley (I was on the brake and slowing to a stop) somehow threw off the belts track over the pulley. I know it's a rough theory, but it's the only strange event I know of that occurred before the weird noise began.

I've included a low-quality iPhone video so you can hear the noise:
A video from my phone | United States | By TempUser38c22e93ded94a476401c81f3ad80d0

Any ideas as to the nature of the noise? You can better hear the high-pitched noise when I rev the engine. I've done some searching around the forum, and this thread has the most similar sounding problem..