This water pump circulates coolant through the engine block and radiator to maintain the engine's operating temperature. It is driven by the engine's accessory belt and uses an impeller to move fluid at a consistent flow rate. A worn pump bearing produces a audible rattle or wobble, and a leaking shaft seal causes coolant loss and overheating. The manufacturer machines the pump housing and impeller to the same dimensional tolerances as the original assembly, so the belt alignment and pulley offset remain unchanged. On installation, replace the gasket on the mounting face and torque the bolts to specification.