Just a thought... there may be indeed something very wrong, but one thing to look into is whether or not your fan clutch is working properly. It sounds to me that your fan remains engaged when it should be free wheeling. That would definitely sound like the engine is screaming. The fan is only supposed to be direct when the motor heats to a certain temperature. But the age of your unit indicates a real possibility that the fan clutch is shot. It is an easy fix if that is the problem. Every auto parts store will carry them...it happens often that they quit working.