A clean radiator the proper size for the engine will keep an engine at or near the opening point of the thermostat. If your engine heats up at idle, you need a cleaner, and/or bigger radiator or more airflow across it. Thy a big rig fan with more blades.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!