ACDelco GM Original Equipment Engine Coolant Water Outlets are housings that connect the radiator hoses to the engine, typically housing the engine coolant thermostat. For certain applications, the water outlet contains threaded holes or ports for sensors and switches. These original equipment engine coolant water outlets 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.