ACDelco GM Original Equipment Engine Crankshaft Pulleys attach to, and are driven by, the front of the engine crankshaft. They connect to various engine accessory drive components by a belt drive system and help ensure that components, such as the water pump, alternator, and power steering pump, receive power from the rotating crankshaft to perform their vital functions. Crankshaft pulleys also work as harmonic dampers to help decrease crankshaft torsional vibration, and are GM-recommended replacements for your vehicles original components. These original equipment engine crankshaft pulleys have been manufactured to fit your GM vehicle, providing the same performance, durability, and service life you expect from General Motors.