The die-cast water pump is a centrifugal vane impeller type. The pump consists of a housing, with coolant inlet and outlet, and an impeller. The impeller is a flat plate mounted on the pump shaft with a series of flat or curved blades, or vanes. When the impeller rotates, the coolant between the blades is thrown outward by centrifugal force. Then the coolant is forced through the pump outlet and into the cylinder block. The pump inlet is connected by a hose to the bottom of the radiator. Coolant from the radiator is drawn into the pump to replace the coolant forced through the outlet.

The impeller shaft is supported on one or more bearings. A seal prevents coolant from leaking out around the bearings. The water pump uses sealed bearings, which never need lubrication. With a sealed bearing, grease cannot leak out, and dirt and water cannot get in.