RE: 2001 Ford Taurus belt squeals
My car is doing the same thing. I have recently replaced the belt twice, using a different brand each time.
It squeals intermittently upon startup about 4 times per second at 1000 rpm. Then after driving a bit it squeals constantly above about 2000 rpm. AC, headlights, power steering don't have any effect. Everything is free to turn.
Even installed new idler wheels. If I spray WD40 or water on the belt, it stops immediately. The pulley's are clean. It's been a couple of months now but just can't figure it out.