Thermostat Housing Crossover Replacement 6.6L (LB7) Engine

1. Loosen the outlet duct clamp at the upper intake manifold cover.
2. Remove the upper intake manifold cover from the outlet duct.
3. Remove the upper intake manifold cover.
4. Drain the cooling system. Refer to Cooling System Draining and Filling .
5. Disconnect the negative battery cables. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.
6. Remove the upper fan shroud. Refer to Engine Coolant Fan Upper Shroud Replacement .
7. Remove the drive belt. Refer to Drive Belt Replacement in Engine Mechanical - 6.6L.



8. Disconnect the air conditioning (A/C) compressor clutch electrical connector (5).
9. Disconnect the A/C cut out switch electrical connector.



10. Remove the A/C compressor bolts.
11. Move the A/C compressor with the hoses attached to the right side of the engine compartment.



12. Remove the generator positive cable to generator nut.
13. Remove the positive cable from the generator.
14. Remove the clip holding the positive cable to the engine front cover.
15. Remove the battery positive cable junction block to power steering pump bolt.
16. Move the generator positive cable and the junction block bracket aside.



17. Disconnect the generator electrical connector (1).
18. Disconnect the engine coolant temperature (ECT) sensor electrical connector.



19. Remove the power steering pump bracket and secure to the side.

•	Do not remove the power steering pump from the bracket.

•	The hoses and battery cables can remain on the power steering pump.




20. Remove the fuel bleed valve and positive crankcase ventilation (PCV) oil separator bracket bolt from the generator bracket.



21. Remove the heater outlet hose bracket bolt from the generator bracket.
22. Remove the ribbed idler pulley.
23. Remove the generator bracket and position to the side.

•	The generator does not require removal.

•	The drive belt tensioner does not require removal.

24. Remove the oil fill tube. Refer to Oil Filler Tube Replacement in Engine Mechanical - 6.6L.
25. Remove the water outlet. Refer to Water Outlet Tube Replacement .



26. Remove the heater inlet pipe to fuel filter bolt.
27. Remove the heater inlet pipe with O-ring seal from the crossover.



28. Remove the turbocharger coolant return pipe clamps and hose.
29. Remove the fuel line bracket from the thermostat housing crossover.
30. Remove the cooling fan pulley. Refer to Cooling Fan Pulley Replacement .



31. Remove the thermostat housing bolts and nuts from the left cylinder head.
32. Remove the thermostat housing bolts and nuts from the right cylinder head.
33. Remove the bypass pipe to water pump bolts.
34. Remove the thermostat housing with the bypass pipe.
35. Remove the bypass pipe to water pump O-ring.



36. Remove the bypass pipe from the thermostat housing.
37. Remove the O-ring from the bypass pipe.



38. Remove the thermostat cover bolts.
39. Remove the thermostat cover.
40. Remove the thermostats with seals.
41. Remove the thermostat seals.
42. If required, clean and inspect the thermostat housing. Refer to Engine Coolant Thermostat Housing Cleaning and Inspection in Engine Mechanical - 6.6L.

1. Install the thermostats with the seals.

The thermostat with the vent valves goes toward the rear of the engine. Install with the vent valves towards the rear of the engine.

2. Install the thermostat cover and gasket.

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 thermostat cover bolts.

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




4. Install a new O-ring to the bypass pipe. Lubricate the O-ring with coolant.
5. Install the bypass pipe to the thermostat housing crossover.



6. Install NEW thermostat housing gaskets.
7. Install a NEW O-ring for the bypass pipe to the water pump.
8. Install the thermostat housing with the bypass pipe.
9. Install the bypass pipe to water pump bolts.

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

10. Install the thermostat housing bolts and nuts.

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

11. Install the fuel line bracket and bolt.

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




12. Install the turbocharger coolant return pipe hose and clamps.
13. Install the cooling fan pulley. Refer to Cooling Fan Pulley Replacement .



14. Install a NEW O-ring seal to the heater inlet pipe.
15. Install the heater inlet pipe to the thermostat housing crossover.
16. Install the heater inlet pipe to thermostat housing crossover bolt.

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

17. Install the heater inlet pipe to fuel filter bolt.

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




18. Install the generator bracket and bolts.

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

19. Install the ribbed idler pulley and the bolt.

Tighten
Tighten the bolt to 43 N·m (32 lb ft).

20. Install the heater outlet hose bracket bolt.

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




21. Install the fuel bleed valve and PCV oil separator bracket nuts to the generator bracket.

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




22. Install the power steering pump bracket and bolts.

Tighten
Tighten the bolts to 46 N·m (34 lb ft).

23. Install the water outlet. Refer to Water Outlet Tube Replacement .



24. Position the generator positive cable.
25. Install the generator positive cable in the clip on the engine front cover.
26. Install the generator positive cable nut.

Tighten
Tighten the nut to 9 N·m (80 lb in).

27. Install the battery positive cable junction block bracket and bolt to the power steering pump.

Tighten
Tighten the bolt to 9 N·m (80 lb in).




28. Connect the ECT sensor electrical connector.
29. Connect the generator electrical connector (1).



30. Position the A/C compressor.
31. Install the A/C compressor bolts.

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




32. Connect the A/C cut out switch electrical connector.
33. Connect the A/C compressor clutch electrical connector (5).
34. Install the drive belt. Refer to Drive Belt Replacement in Engine Mechanical - 6.6L.
35. Install the upper fan shroud. Refer to Engine Coolant Fan Upper Shroud Replacement .
36. Fill the cooling system. Refer to Cooling System Draining and Filling .
37. Connect the negative battery cables. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.



38. Install the upper intake manifold cover.
39. Install the upper intake manifold cover to the outlet duct.
40. Tighten the outlet duct clamp at the upper intake manifold cover.

Tighten
Tighten the clamp to 6 N·m (53 lb in).

Thermostat Housing Crossover Replacement 6.6L (LLY) Engine

1. Remove the intake manifold cover. Refer to Intake Manifold Cover Replacement in Engine Mechanical - 6.6L (LLY).
2. Drain the cooling system. Refer to Cooling System Draining and Filling .
3. Disconnect the negative battery cables. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.
4. Remove the upper fan shroud. Refer to Engine Coolant Fan Upper Shroud Replacement .
5. Remove the drive belt. Refer to Drive Belt Replacement in Engine Mechanical - 6.6L (LLY).
6. Disconnect the air conditioning (A/C) compressor clutch electrical connector (5).
7. Disconnect the A/C cut out switch electrical connector.



8. Remove the A/C compressor bolts.
9. Reposition the A/C compressor, with the hoses attached, to the right side of the engine compartment.



10. Remove the generator positive cable to generator nut.
11. Remove the positive cable from the generator.
12. Remove the clip holding the positive cable to the engine front cover.
13. Remove the battery positive cable junction block to power steering pump bolt (1).
14. Move the generator positive cable and the junction block bracket aside.



15. Disconnect the generator electrical connector.
16. Disconnect the engine coolant temperature (ECT) sensor electrical connector.



17. Remove the power steering pump bracket bolts.
18. Reposition the power steering pump bracket and secure to the side.

•	Do not remove the power steering pump from the bracket.

•	The hoses and battery cables can remain on the power steering pump.




19. Remove the heater outlet hose bracket bolt from the generator bracket.
20. Remove the idler pulley.
21. Remove the generator bracket bolts.
22. Remove the generator bracket and position to the side.

•	The generator does not require removal.

•	The drive belt tensioner does not require removal.

23. Remove the oil fill tube. Refer to Oil Filler Tube Replacement in Engine Mechanical - 6.6L (LLY).
24. Remove the water outlet. Refer to Water Outlet Tube Replacement .



25. Reposition the exhaust gas recirculation (EGR) hose clamp at the EGR coolant pipe.
26. Remove the EGR coolant pipe bolt.
27. Remove the EGR coolant pipe with O-ring seal from the crossover.



28. Reposition the turbocharger coolant return pipe hose clamp.
29. Remove the turbocharger coolant return pipe hose.



30. Remove the fuel line bracket bolt at the thermostat housing crossover.
31. Remove the cooling fan pulley. Refer to Cooling Fan Pulley Replacement .



32. Remove the water pump inlet pipe bolts.



33. Remove the thermostat housing bolts and nuts.
34. Remove the thermostat housing, with the bypass pipe.
35. Remove and discard the thermostat bypass pipe to water pump O-ring seal.
36. Remove and discard the thermostat housing gaskets.
37. If necessary, perform the following steps:

37.1.

Remove the thermostat bypass pipe from the thermostat housing.

37.2.

Remove and discard the thermostat bypass pipe O-ring seal.

37.3.

Remove the thermostat cover bolts and cover.

37.4.

Remove the thermostats.

37.5.

Remove and discard the thermostat seals.

38. If required, clean and inspect the thermostat housing. Refer to Engine Coolant Thermostat Housing Cleaning and Inspection in Engine Mechanical - 6.6L (LLY).

1. If necessary, perform the following steps:

1.1.	Install NEW seals to the thermostats.

1.2.	Install the thermostats.

Notice: Refer to Fastener Notice in the Preface section.

1.3.	Install the thermostat cover and bolts.

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

1.4.	Install a NEW O-ring seal to the thermostat bypass pipe.

1.5.	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 using NEW gaskets.
4. Install the thermostat housing bolts and nuts

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




5. Install the water pump inlet pipe bolts.

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

6. Install the cooling fan pulley. Refer to Cooling Fan Pulley Replacement .



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

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




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



10. Install the EGR coolant pipe with O-ring seal to the crossover.
11. Install the EGR coolant pipe bolt.

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

12. Position the EGR hose clamp at the EGR coolant pipe.
13. Install the water outlet. Refer to Water Outlet Tube Replacement .
14. Install the oil fill tube. Refer to Oil Filler Tube Replacement in Engine Mechanical - 6.6L (LLY).



15. Position the generator bracket.
16. Install the generator bracket bolts.

Tighten
Tighten the bolt to 50 N·m (37 lb ft).

17. Install the idler pulley.

Tighten
Tighten the bolt to 43 N·m (32 lb ft).

18. Install the heater outlet hose bracket bolt to the generator bracket.

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




19. Position the power steering pump bracket.
20. Install the power steering pump bracket bolts.

Tighten
Tighten the bolt to 46 N·m (34 lb ft).




21. Position the generator positive cable and the junction block bracket.
22. Install the battery positive cable junction block to power steering pump bolt (1).

Tighten
Tighten the bolt to 9 N·m (80 lb in).

23. Install the clip holding the positive cable to the engine front cover.
24. Install the positive cable to the generator.
25. Install the generator positive cable to generator nut.

Tighten
Tighten the nut to 9 N·m (80 lb in).




26. Connect the ECT sensor electrical connector.
27. Connect the generator electrical connector.



28. Position the A/C compressor, with the hoses attached.
29. Install the A/C compressor bolts.

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




30. Connect the A/C cut out switch electrical connector.
31. Connect the A/C compressor clutch electrical connector (5).
32. Install the drive belt. Refer to Drive Belt Replacement in Engine Mechanical - 6.6L (LLY).
33. Install the upper fan shroud. Refer to Engine Coolant Fan Upper Shroud Replacement .
34. Connect the negative battery cables. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.
35. Fill the cooling system. Refer to Cooling System Draining and Filling .
36. Install the intake manifold cover. Refer to Intake Manifold Cover Replacement in Engine Mechanical - 6.6L (LLY).