GM Genuine Parts Engine Crankshaft Seals are designed, engineered, and tested to rigorous standards, and are backed by General Motors. These seals are high quality radial shaft seals, which seal in engine oil and keep dirt and water out. Made from synthetic rubber or plastic composite materials, these engine crankshaft seals conform to the rotating crankshaft sealing surface to help provide leak-free operation. GM Genuine Parts are the true OE parts installed during the production of or validated by General Motors for GM vehicles. Some GM Genuine Parts may have formerly appeared as ACDelco GM Original Equipment (OE).