Water Pump Replacement 4.3L, 5.0L, and 5.7L

1. Disconnect the negative battery cable from the battery terminal. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.
2. Remove the air cleaner assembly. Refer to one of the following procedures:

•	Air Cleaner Assembly Replacement in Engine Controls - 4.3L

•	Air Cleaner Assembly Replacement in Engine Controls - 5.0L and 5.7L

3. Drain the engine cooling system. Refer to Cooling System Draining and Filling .



4. Remove the air intake duct from the throttle body.
5. Remove the coolant recovery reservoir. Refer to Coolant Recovery Reservoir Replacement .
6. Remove the upper fan shroud. Refer to Fan Shroud Replacement .
7. Remove the fan clutch assembly from the vehicle. Refer to Fan Clutch Replacement .
8. Remove the drive belt from the vehicle. Refer to one of the following procedures:

•	Drive Belt Replacement in Engine Mechanical - 4.3L

•	Drive Belt Replacement in Engine Mechanical - 5.0L and 5.7L




9. Remove the water pump pulley mounting bolts.
10. Remove the water pump pulley from the water pump.



11. Disconnect the radiator outlet hose from the water pump.



12. Disconnect the by-pass hose from the water pump.



13. Remove the heater outlet hose from the water pump.



14. Remove the water pump mounting bolts.
15. Remove the water pump and the gasket.
16. Clean and inspect the sealing surfaces of the engine block.
17. Clean the water pump mounting bolts, and inspect the threads for damage.

1. Install the gasket and the water coolant pump.
2. Apply Teflon Pipe Sealant GM P/N 12346004 or equivalent thread sealant on the water pump mounting bolts.

Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

3. Install the water pump mounting bolts.

Tighten
Tighten the bolts to 42 N·m (31 lb ft).




4. Install the heater outlet hose to the water pump.



5. Install the by-pass hose to the water pump.



6. Connect the radiator outlet hose to the water pump.



7. Install the water pump pulley to the water pump.
8. Install the water pump pulley mounting bolts.

Tighten
Tighten the bolts to 25 N·m (18 lb ft).

9. Install the drive belt in the vehicle. Refer to one of the following procedures:

•	Drive Belt Replacement in Engine Mechanical - 4.3L

•	Drive Belt Replacement in Engine Mechanical -5.0L and 5.7L

10. Install the fan clutch in the vehicle. Refer to Fan Clutch Replacement .
11. Install the upper fan shroud. Refer to Fan Shroud Replacement .
12. Install the coolant recovery reservoir. Refer to Coolant Recovery Reservoir Replacement .



13. Install the air intake duct to the throttle body.
14. Install the air cleaner assembly in the vehicle. Refer to one of the following procedures:

•	Air Cleaner Assembly Replacement in Engine Controls - 4.3L

•	Air Cleaner Assembly Replacement in Engine Controls - 5.0L and 5.7L

15. Connect the battery negative cable to the battery terminal. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.

Notice: When adding coolant, use DEX-COOL® coolant. If silicated coolant is added to the system, premature engine, heater core or radiator corrosion may result. In addition, the engine coolant will require change sooner-at 50 000 km (30,000 mi) or 24 months.

16. Refill the engine coolant system. Refer to Cooling System Draining and Filling .
17. Bleed the air from the cooling system.
18. Inspect the system for coolant leaks.

Water Pump Replacement 6.5L

1. Disconnect both negative battery cables from the batteries. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.
2. Drain the engine cooling system. Refer to Cooling System Draining and Filling .
3. Remove the air cleaner assembly from the vehicle. Refer to Air Cleaner Assembly Replacement in Engine Controls - 6.5L (L65).



4. Remove the air intake duct from the turbocharger.
5. Remove the surge tank from the vehicle. Refer to Radiator Surge Tank Replacement .
6. Remove the upper fan shroud from the radiator. Refer to Fan Shroud Replacement .
7. Remove the fan clutch from the water pump pulley. Refer to Fan Clutch Replacement .
8. Remove the drive belt from the vehicle. Refer to Drive Belt Replacement in Engine Mechanical - 6.5L.



9. Remove the water pump pulley mounting bolts.
10. Remove the water pump pulley from the water pump.



11. Disconnect the radiator outlet hose from the water pump.



12. Disconnect the by-pass hose from the water pump.
13. Remove the generator mounting bracket from the engine block. Refer to Generator Bracket Replacement in Engine Electrical.
14. Remove the engine lift bracket from the engine block. Refer to Engine Lift Bracket Replacement in Engine Mechanical - 6.5L.



15. Remove the water pump mounting bolts.
16. Remove the water pump assembly from the engine front cover.



17. Remove the bolts from the back of the water pump backing plate.
18. Remove the water pump from the backing plate.
19. Remove the gasket from the water pump backing plate.
20. Clean and inspect the gasket sealing surfaces of the engine front cover and water pump backing plate.
21. Clean all the water pump mounting bolts.

Important: When servicing the water pump assembly, do not apply any sealant to the water pump gasket. The water pump gasket is manufactured with the proper amount of sealant printed on it.

1. Install the water pump gasket.



2. Apply a bead of anerobic sealer GM P/N 1052942 or the equivalent to the water pump plate.
3. Install the water pump to the backing plate.
4. Apply high temperature thread adhesive GM P/N 12345493 or equivalent, to the bolt threads.

Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

5. Install the mounting bolts behind the water pump plate.

Tighten
Tighten the water pump plate bolts to 28 N·m (20 lb ft).




6. Install the water pump and backing plate to the engine.

The sealer must be wet to the touch when installing the plate.

7. Apply Teflon Pipe Sealant GM P/N 123456004 or equivalent to the thread of the bolts and the studs.
8. Install the bolts and the studs.

Tighten

•	Tighten the water pump to the front cover bolts to 42 N·m (32 lb ft).

•	Tighten the water pump plate to the front cover to 28 N·m (20 lb ft).




9. Connect the by-pass hose to the water pump.
10. Install the engine lift bracket to the engine block. Refer to Engine Lift Bracket Replacement in Engine Mechanical - 6.5L.
11. Install the generator mounting bracket to the engine block. Refer to Generator Bracket Replacement in Engine Electrical.



12. Connect the radiator outlet hose to the water pump.



13. Install the water pump pulley to the water pump.
14. Install the water pump pulley mounting bolts.

Tighten
Tighten the water pump pulley mounting bolts to 25 N·m (18 lb ft).

15. Install the drive belt on the vehicle. Refer to Drive Belt Replacement .
16. Install the fan clutch to the water pump pulley. Refer to Fan Clutch Replacement .
17. Install upper radiator shroud on the radiator. Refer to Fan Shroud Replacement .
18. Install the surge tank in the vehicle. Refer to Radiator Surge Tank Replacement .
19. Connect the both battery negative cables to the batteries. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.
20. Refill the engine cooling system. Refer to Cooling System Draining and Filling .
21. Using the following procedures, bleed the air from the engine cooling system.

21.1.

Remove the cap from the surge tank.

21.2.

Remove the bleed screw (slotted) from the top of the thermostat housing.

21.3.

Pour coolant into the surge tank, and watch for coolant flowing from the bleed screw.

21.4.

When a constant flow of coolant is reached, closed the bleed screw at the top of the thermostat housing.

21.5.

Continue to fill the surge tank to the proper level.

21.6.

Install the cap on the surge tank.




22. Install the air intake duct to the turbocharger.
23. Install the air cleaner assembly in the vehicle. Refer to Air Cleaner Assembly Replacement in Engine Controls - 6.5L (L65).
24. Inspect the system for coolant leaks.

Water Pump Replacement 8.1L

1. Drain the cooling system. Refer to Cooling System Draining and Filling .
2. Remove the drive belt tensioner. Refer to Drive Belt Tensioner Replacement in Engine Mechanical - 8.1L.
3. Remove the fan. Refer to Fan Clutch Replacement .
4. Reposition the outlet hose clamp at the water pump.
5. Disconnect the outlet hose (2) from the water pump.



6. Reposition the bypass hose clamps at the water pump and crossover.
7. Remove the bypass hose.



8. Remove the water pump bolts.
9. Remove the water pump and gaskets.

1. Place NEW water pump gaskets and the water pump into position.

Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

2. Install the water pump bolts.

Tighten
Tighten the water pump bolts to 50 N·m (37 lb ft).




3. Install the bypass hose.
4. Position the bypass hose clamps at the water pump and crossover.



5. Install the outlet hose (2) to the water pump.
6. Position the outlet hose clamp at the water pump.
7. Install the fan. Refer to Fan Clutch Replacement .
8. Install the drive belt tensioner. Refer to Drive Belt Tensioner Replacement in Engine Mechanical - 8.1L.
9. Fill the cooling system. Refer to Cooling System Draining and Filling .