Water Pump: Service and Repair

Removal Procedure





1. Drain the coolant from the radiator. Refer to Draining and Filling Cooling System.
2. Remove the fan shroud.
^ For the upper shroud, refer to Fan Shroud Replacement (Upper).
^ For the lower shroud, refer to Fan Shroud Replacement (Lower).
3. Remove the drive belt. Refer to Drive Belt Replacement.
4. Remove the fan and fan clutch. Refer to Fan Clutch Replacement.
5. Raise the vehicle. Support the vehicle with safety stands. Refer to Vehicle Lifting.
6. Remove the following vacuum pump components. Refer to Vacuum Pump Replacement:
6.1. The mounting bracket nuts
6.2. The bolt securing the vacuum pump bracket and the generator
6.3. The vacuum pump and the bracket
7. Remove the power steering pump. Do not disconnect the hoses. Lay the pump aside. Refer to Power Steering Pump Replacement.
8. Lower the vehicle.
9. Disconnect the lower radiator hose from the coolant pump. Refer to Radiator Hose Replacement.
10. Disconnect the bypass hose from the coolant pump.
11. Remove the bolts, the studs, the coolant pump backing plate and the coolant pump.





12. Remove the bolt from the rear of the coolant pump backing plate.
13. Remove the coolant pump and the gasket from the backing plate.

Important: All of the flanges must be free of oil.

14. Clean the following mating surfaces:
^ The coolant pump
^ The coolant pump backing plate (both sides)
^ The engine block


Installation Procedure





1. Install the gasket.
2. Install the water pump to the water pump backing plate.
3. Apply high temperature thread adhesive GM P/N 12345493, or equivalent, to the bolt threads.

Notice: Refer to Fastener Notice in Service Precautions.

4. Install the bolts.
^ Tighten the bolt to 28 Nm (20 ft. lbs.).





5. Apply anaerobic sealer GM P/N 1052942, or equivalent to the water pump backing plate. The sealer must be wet to the touch when the bolts are installed and tightened.





6. Install the coolant pump and the coolant pump backing plate to the engine.
7. Install the bolts and the studs.
^ Tighten the water pump to front cover bolts to 42 Nm (31 ft. lbs.).
^ Tighten the water pump plate to front cover bolts to 28 Nm (20 ft. lbs.).
8. Connect the bypass hose.
9. Connect the lower radiator hose. Refer to Radiator Hose Replacement.
10. Install the power steering bracket and the pump. Refer to Power Steering Pump Replacement.
11. Raise the vehicle. Refer to Vehicle Lifting.
12. Install the vacuum pump and the bracket. Refer to Vacuum Pump Replacement.
13. Lower the vehicle.
14. Install the fan and fan clutch assembly and the coolant pump pulley. Refer to Fan Clutch Replacement.
15. Install the drive belt. Refer to Drive Belt Replacement.
16. Install the fan shroud.
^ For the upper shroud, refer to Fan Shroud Replacement (Upper).
^ For the lower shroud, refer to Fan Shroud Replacement (Lower).
17. Fill the surge tank with coolant. Refer to Draining and Filling Cooling System.
18. Start the engine. Run the engine with the surge tank cap removed, until the upper radiator hose becomes hot. (This indicates that the thermostat is open).
19. While the engine is running at idle speed, add coolant to the surge tank until the level reaches the FULL mark. Refer to Draining and Filling Cooling System.





20. Install the surge tank cap. Make sure the cap arrows line up with the overflow tube.
21. Inspect the cooling system for leaks.