A thermostat controls the flow of coolant in your engine. By staying closed a thermostat allows your engine to get up to operating temperature faster. Once at operating temperature the thermostat opens allowing full circulation of coolant. When your factory thermostat begins to fail you will notice an increase in coolant temperatures and sometimes overheating. Replace your failing thermostat today with this new OEM thermostat. Also included is a new o-ring. Don’t forget to purchase coolant!