ACDelco 251-591 GM Original Equipment Water Pump with Cover Gasket Thoroughly tested for reliable, leak-free performance Uniform wall sections and smooth coolant-flow cavities for efficient operation Coated seals with a stainless steel spring for durability Heat-treated impeller shafts supported by high-quality ball/roller bearings for smooth, reliable operation in virtually all conditions GM-recommended replacement part for your GM vehicles original factory water pump