160 vs. 180 thermostat what the differance?

[Bob Putnam]

Monster,

With adequate airflow through the radiator, a 160F thermostat will keep the temperature 20F lower than a 180F thermostat. When you are depending on the fan for airflow things are a little different. The temperature may be dependant solely on the difference between the ambient air temperature and the engine's. Once the engine temperature goes above 180F, both thermostats are fully open and you are getting maximum flow. Below that, the thermostat will "throttle down" the flow to match its rating.

An engine has an operating range where lubrication and fuel mixtures are optimum. Running with the oil too cool will allow water and fuel condensates to build up, plus oil flow will be reduced to many critical areas.