Thermostat: Description and Operation
THERMOSTATThe engine cooling thermostats are a wax pellet driven, reverse poppet choke type. They are designed to provide the fastest warm up possible by preventing leakage through them and to guarantee a minimum engine operating temperature of 88° to 93°C (192° to 199°F). They also automatically reach wide open so they do not restrict flow to the radiator as temperature of the coolant rises in hot weather to around 104°C (220°F). Above this temperature the coolant temperature is controlled by the fan, the radiator, and the ambient temperature, not the thermostat.