ACDelco GM Original Equipment Engine Coolant Thermostat Housings are used in some makes and models. The housing holds the thermostat and isconnection point for the radiator hose inlet or outlet, and may also include ports for sensors or switches. These original equipment engine coolant thermostat housings are GM-recommended replacements for your vehicle's original components and have been manufactured to fit your GM vehicle, providing the same performance, durability, and service life you expect from General Motors.