[doctorhrdware]

As stated before it could be the water pump. Remove the serpentine belt and check the water pump. See if the pulley has any play in it, if it does your water pump is on it's way out. It also could be the belt tensioner pulley also. Have you ever replaced the serpentine belt, that maybe the source of the pulley squeal. The wife's chevy pickup the belt squeals until the truck warms up.