This is a "Billet Aluminum Coolant Nipple" for a 1986 or 1987 Buick Grand National, T Type, Turbo T, or GNX 3.8 liter turbo V6. This the nipple that connects the "S bypass hose" between the water pump and the manifold. It replaces the factory rusted out steel nipple with a Billet Aluminum rust resistant one.
