An ACDelco GM Original Equipment Engine Coolant Thermostat is a temperature controlled valve in the engine coolant outlet to or the inlet of the radiator and is a GM recommended replacement for the original part of your vehicle. It controls the coolant flow through the radiator so that the engine can reach and maintain its normal operating temperature. Manufactured for your GM vehicle, this original engine coolant thermostat provides the same performance, durability and life you expect from General Motors.