This thermostat regulates engine coolant flow to maintain the operating temperature of the host tractor. It sits in the thermostat housing on the engine block, controlling the opening and closing of the coolant circuit between the engine and the radiator. A stuck-closed thermostat causes overheating; a stuck-open thermostat prevents the engine from reaching its normal operating temperature, reducing efficiency. This part is manufactured to the original spring-rate and opening-temperature specifications, ensuring the coolant system responds correctly to load changes. On reinstallation, clean the housing sealing surface and use a new gasket.