ACDelco GM Original Equipment Engine Coolant Outlet O-Rings are formed elastomer gaskets that form the water-tight seal between the engine coolant outlet and the engine block or head, and are GM-recommended replacements for your vehicle's original components. Install these O-Rings according to the published service procedures. These original equipment engine coolant outlet O-Rings have been manufactured to fit your GM vehicle, providing the same performance, durability, and service life you expect from General Motors.