I own a 2006 Impreza sedan with 134k miles.  When I started the car today I heard a loud squeal.  I couldn't tell if it was belt, idler pulley or AC clutch bearing.  I removed the idler pulley and checked it.  It seems to be rolling fine and not binding.  Once I put it back together the squeal was gone until I turned on the fan.  When the fan was on it would squeal, when off no squeal.  Anyone else experience this?  Thoughts on repair.  Thanks