GM Genuine Parts Engine Water Pump Pulleys are designed, engineered, and tested to rigorous standards, and are backed by General Motors. These pulleys attach to the water pump shaft and are driven by the engine accessory belt. Replacing worn or bent engine water pump pulleys can help prevent premature wear of the engine accessory belt. 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).