ACDelco GM Original Equipment Engine Coolant Thermostat/Water Inlet Assemblies contain the engine thermostat and water inlet housing and are GM-recommended replacements for your vehicle’s original components. The engine coolant thermostat controls the flow of coolant through the radiator to enable the engine to reach and maintain its normal operating temperature. The water inlet housing connects the radiator hoses to the thermostat. For certain applications, the water inlet contains threaded holes or ports for sensors and switches. These original equipment engine coolant thermostat/water inlet assemblies have been manufactured to fit your GM vehicle, providing the same performance, durability, and service life you expect from General Motors.