Originally posted by atomarc:
Waggy,
I will amend my thinking based on some of the above posts. Changing thermostats will have absolutely no bearing on the temperature your engine runs. Engine operating temperature is a factor designed in by the engineers in Detroit and has nothing to do with your cooling system. You will have to buy a new engine that has been designed to run at a lower temperature, then the cooling system you now have will be able handle it.
The key point here is that thermostat rating and the operating temperature of the engine have nothing at all to do with each other. I quote [b]"normal operating temp will not be related to stat temp". 
Stuart [/b]
Not entirely correct, as installing a higher temp stat WILL raise normal operating temp, but a lower stat may or may not lower normal operating temp. Yes, the stat would open sooner, but it would not neccessarily lower the normal operating temp. It gets real hot down here, I've never seen a 350 in anything run 180* using a 180* stat or 195* w/a 195* stat, they always run higher. Yes, most late model cooling systems are designed to run 210*+ for emissions.
Generally speaking, if you are having an overheating problem, a lower temp stat will not help, the engine will build heat regardless of the temp of the stat opening.
