The thermostat Figure 2-55 is placed in the coolant passage between the cylinder head and the top of the radiator. Its purpose is to close off this passage when the engine is cold so that coolant circulation is restricted. This allows the engine to reach normal operating temperature more rapidly. The thermostat is designed to open at a specific temperature (180 °F).
When the engine is cold and the thermostat is closed and coolant recirculates thru the cylinder head and case. When the thermostat opens, the coolant circulates through the radiator.
1982 – Early 1983 Engines 180°
1983 and Later 190°
