engine wizzes and heats up.

What is your question?

engine wizzes and heats up. sometimes the coolant is full and other times its drained. When is starts to wiz loudly as the rpm goes up and down is when it starts to heat up. It has a new radiator and thermostat housing although I've had it heat up when the coolant was full.

What makes this problem better or worse?

when pulling a trailer

How long has your 2007 Mercury Mountaineer had this problem?

a couple of years