Car: 98 GT I noticed that I've been getting a slight squeal from the engine bay lately so I figured it was the tensioner or idler pulley going. I opened the hood and listened and it seemed to be coming from that area. It was king of hard to tell considering the coils, ac lines, and radiator hose. I replace the idler and nothing changed. I then swapped the tensioner pulley for the idler and nothing changed. I took the belt off completely and spun all of the pulleys and couldn't really make sense of it so I figured that I'd look more at the ac clutch and pulley. If I turned the ac on then the noise was almost gone and if I turned it off than it would be loud again. I figured the only logical thing would be that the bearing in the pulley was bad. So I replaced it with the $14 dollar Santech bearing from autozone and now it's even louder. I'm racking my brain here trying to figure this out because it seems so obvious. I turn the ac on then the hub spins with the pulley and the noise goes away. I turn it off and the noise comes back. If it were the compressor bearing than I would get noise while it's spinning and not stationary while it's not engaged I'd think. Am I missing something obvious that I'm over looking?