Thermostat Housing Crossover Replacement (LMM)

Thermostat Housing Crossover Replacement (LMM) (6.6L)

Removal Procedure





1. Remove the air cleaner. Refer to Air Cleaner Assembly Replacement .
2. Drain the cooling system. Refer to Cooling System Draining and Filling (Vac-N-Fill) (Service and Repair)Cooling System Draining and Filling (Static Fill) (Service and Repair) .
3. Disconnect the negative battery cables. Refer to Battery Negative Cable Disconnection and Connection (w/Single Battery) Battery Negative Cable Disconnection and Connection (w/Auxiliary Battery) Battery Negative Cable Disconnection and Connection (w/Dual Batteries) .
4. Remove the drive belt. Refer to Drive Belt Replacement (Service and Repair) .
5. Disconnect the air conditioning (A/C) pressure switch electrical connector (1).
6. Disconnect the A/C compressor clutch electrical connector (2).
7. Remove the generator bracket. Refer to Generator Bracket Replacement (4.3L) Generator Bracket Replacement (4.8L, 5.3L, 6.0L, and 6.2L) Generator Bracket Replacement (6.6L) .
8. Remove the front oil fill tube. Refer to Oil Filler Tube Replacement (Oil Filler Tube Replacement) .




9. Disconnect the engine coolant temperature (ECT) sensor electrical connectors.
10. Remove the water outlet. Refer to Water Outlet Tube Replacement (LMM) (Service and Repair)Water Outlet Tube Replacement (LU3) (Service and Repair) .
11. Without disconnecting the power steering hoses, remove the power steering pump bolts and the power steering pump. Reposition the power steering pump and secure to the side. Refer to Power Steering Pump Replacement (4.3L) Power Steering Pump Replacement (4.8L, 5.3L, 6.0L, and 6.2L) Power Steering Pump Replacement (6.6L) .
12. Remove the power steering pump bracket. Refer to Air Conditioning (A/C) Compressor and Power Steering Pump Bracket Replacement (Service and Repair) .




13. Remove the bolts and wiring harness bracket at the thermostat housing.
14. Position the bracket and wiring harness aside.
15. Remove the cooling fan pulley. Refer to Cooling Fan Pulley Replacement (Service and Repair) .




16. Reposition the turbocharger coolant return pipe hose clamp.
17. Remove the turbocharger coolant return pipe hose.




18. Remove the fuel line bracket bolt at the thermostat housing crossover.




19. Remove the water pump inlet pipe bolts.




20. Remove the thermostat housing crossover bolts and nuts.
21. Remove the thermostat housing crossover, with the bypass pipe.
22. Remove and discard the thermostat bypass pipe to water pump O-ring seal.
23. Remove and discard the thermostat housing crossover gaskets.
24. If necessary, perform the following:

1. Remove the thermostat bypass pipe from the thermostat housing crossover.
2. Remove and discard the thermostat bypass pipe O-ring seal.
3. Remove the thermostat cover bolts and cover.
4. Remove the thermostats.
5. Remove and discard the thermostat seals.

25. If required, clean and inspect the thermostat housing. Refer to Engine Coolant Thermostat Housing Cleaning and Inspection () .



Installation Procedure






Notice: Refer to Fastener Notice .

1. If necessary, perform the following:

1. Install NEW seals to the thermostats.
2. Install the thermostats.
3. Install the thermostat cover and bolts.

Tighten the bolts to 21 N.m (15 lb ft).

4. Install a NEW O-ring seal to the thermostat bypass pipe.
5. Install the thermostat bypass pipe to the thermostat housing.

2. Install a NEW thermostat bypass pipe to water pump O-ring seal.
3. Install the thermostat housing crossover using NEW gaskets.
4. Install the thermostat housing crossover bolts and nuts.

Tighten the bolts/nuts to 21 N.m (15 lb ft).





5. Install the water pump inlet pipe bolts.

Tighten the bolts to 21 N.m (15 lb ft).





6. Install the fuel line bracket bolt at the thermostat housing crossover.

Tighten the bolt to 21 N.m (15 lb ft).





7. Install the turbocharger coolant return pipe hose.
8. Position the turbocharger coolant return pipe hose clamp.




9. Install the wiring harness bracket and bolts to the thermostat housing.

Tighten the bolts to 10 N.m (89 lb in).

10. Install the cooling fan pulley. Refer to Cooling Fan Pulley Replacement (Service and Repair) .
11. Install the power steering pump bracket. Refer to Air Conditioning (A/C) Compressor and Power Steering Pump Bracket Replacement (Service and Repair) .
12. Reposition the power steering pump and install the power steering pump bolts. Refer to Power Steering Pump Replacement (4.3L) Power Steering Pump Replacement (4.8L, 5.3L, 6.0L, and 6.2L) Power Steering Pump Replacement (6.6L) .




13. Install the water outlet. Refer to Water Outlet Tube Replacement (LMM) (Service and Repair)Water Outlet Tube Replacement (LU3) (Service and Repair) .
14. Connect the ECT sensor electrical connectors.
15. Install the front oil fill tube. Refer to Oil Filler Tube Replacement (Oil Filler Tube Replacement) .
16. Install the generator bracket. Refer to Generator Bracket Replacement (4.3L) Generator Bracket Replacement (4.8L, 5.3L, 6.0L, and 6.2L) Generator Bracket Replacement (6.6L) .




17. Connect the A/C compressor clutch electrical connector (2).
18. Connect the A/C cut out switch electrical connector (1).
19. Install the drive belt. Refer to Drive Belt Replacement (Service and Repair) .
20. Connect the negative battery cables. Refer to Battery Negative Cable Disconnection and Connection (w/Single Battery) Battery Negative Cable Disconnection and Connection (w/Auxiliary Battery) Battery Negative Cable Disconnection and Connection (w/Dual Batteries) .
21. Fill the cooling system. Refer to Cooling System Draining and Filling (Vac-N-Fill) (Service and Repair)Cooling System Draining and Filling (Static Fill) (Service and Repair) .
22. Install the air cleaner. Refer to Air Cleaner Assembly Replacement .