ACDelco GM Original Equipment Engine Water Pump Gaskets are used between the water pump housing and the engine block or another component to seal the interface between the components. The gasket may be made of fiber or a rubberized composite material that provides a liquid-tight connection. The gasket keeps the engine coolant in and keeps air out. These original equipment gaskets have been manufactured to fit your GM vehicle, providing the same performance, durability, and service life you expect from General Motors.