ACDelco GM Original Equipment Engine Coolant Thermostat Housings are used in some makes and models. The housing holds the thermostat and is a connection 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 vehicleÆs original components and have been manufactured to fit your GM vehicle, providing the same performance, durability, and service life you expect from General Motors. WARNING: Cancer and Reproductive Harm