My vehicle is a '91 300-SEL - M103 engine. The car is fine at the moment. I have a cooling system question I'd like to confer with other list members about.

I've heard that if revving the engine of an overheated vehicle reduces the engine temp, the thermostat is defective?

Is there any truth to this? If not and revving does reduce engine temp, what does this indicate? Thanks for your time.

Mike Murrell