Cardone 58-421 Remanufactured Domestic Water Pump Units feature new, unitized ceramic seal assemblies. Unitized seals are made as one piece, which minimizes premature seal wear. Ball/Ball or Ball/Roller bearings are used as specified by O.E. for like new performance. Impellers are electronically gauged to ensure a proper press fit Applications with high off-set loads are upgraded to Ball/Roller bearings to ensure long bearing life. Every unit is 100% leak tested and hub-pulled to ensure quality and reliability. A cooling system maintenance check should be performed at least once every two years. Consult vehicles service manual for specific guidelines on cooling system. A hydrometer can be used to measure specific gravity of coolant. A refractometer can be used to determine coolant concentration and freeze point. Check coolant level. Adjust level if necessary with correct coolant mixture. The engine overheating could be due to components other than the water pump. The following steps should be taken before checking the pump. Flush the system. Check hoses, clamps and seals. Check radiator cap and thermostat. Check for proper and sufficient coolant. Check for cracks, warpage and other damage.