The purpose of the thermostat is to keep the engine temp where the engineers believe it performs the best. Yes it does help it warm up faster than no thermostat but it also allows the coolant to flow at a slower rate through the radiator. If your cooling system is up to snuff your engine should never run above the stats temp rating. What I am trying to say is changing to a higher temp stat is NOT going to solve your issue. Look at all the things in the previous posts to resolve your problem. I put a 180 failsafe in my new engine last night.