Thermostat is in the internal combustion engine cooling system, used to maintain the engine near its optimum operating temperature by regulating the flow of coolant to an air-cooled radiator. This type of thermostat operates using a sealed chamber containing a wax pellet that melts and expands at a set temperature. The expansion of the chamber operates a rod which opens a valve when the operating temperature is exceeded.
The operating temperature is determined by the composition of the wax. Once the operating temperature is reached, the thermostat progressively increases or decreases its opening in response to temperature changes, dynamically balancing the coolant recirculation flow and coolant flow to the radiator to maintain the engine temperature in the optimum range.
Position in cooling system
Basic work diagram