Escalade, Suburban, Tahoe, Yukon, Denali, DenaliXL, YukonXL 1999-2005

Removal & Installation

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CAUTION
Never open, service or drain the radiator or cooling system when hot; serious burns can occur from the steam and hot coolant. Also, when draining engine coolant, keep in mind that cats and dogs are attracted to ethylene glycol antifreeze and could drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantities. Always drain coolant into a sealable container. Coolant should be reused unless it is contaminated or is several years old.

4.3L, 5.0L, 5.7L And 7.4L Engines




CAUTION
Never open, service or drain the radiator or cooling system when hot; serious burns can occur from the steam and hot coolant. Also, when draining engine coolant, keep in mind that cats and dogs are attracted to ethylene glycol antifreeze and could drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantities. Always drain coolant into a sealable container. Coolant should be reused unless it is contaminated or is several years old.

  1. Drain the radiator until the coolant is below the thermostat level (below the level of the intake manifold).
  2.  
  3. Remove the water outlet elbow assembly from the engine. Remove the thermostat from the engine, or, on the 4.8L, from inside the adapter elbow.
  4.  

To install:

  1. Clean the gasket surfaces on the water outlet elbow and the intake manifold. Use a new gasket when installing the elbow to the manifold.
  2.  
  3. Install the new thermostat making sure the spring side is inserted into the engine. Tighten the thermostat housing bolts to:

    4.3L, 5.0L, 5.7L tighten the studs to 21 ft. lbs. (28 Nm)
     
    7.4L tighten the bolts to 27 ft. lbs. (37 Nm).
     

  4.  
  5. Refill the cooling system. Start the engine and check for leaks.

    Click image to see an enlarged view

    Fig. Remove the thermostat housing bolts



    Click image to see an enlarged view

    Fig. Remove the thermostat housing from the engine



    Click image to see an enlarged view

    Fig. Remove the thermostat from the housing



    Click image to see an enlarged view

    Fig. Thermostat housing-4.3L engines



    Click image to see an enlarged view

    Fig. Thermostat housing-5.0L and 5.7L engines



    Click image to see an enlarged view

    Fig. Thermostat housing-7.4L engines C/K series

  6.  

4.8L, 5.3L & 6.0L Engines



  1. Remove the air inlet duct.
  2.  
  3. Drain the cooling system.
  4.  
  5. Remove the radiator outlet hose.
  6.  
  7. Remove the thermostat housing bolts.
  8.  
  9. Remove the thermostat from the water pump housing.
    NOTE
    The O-ring seal is integral to the thermostat housing



    Click image to see an enlarged view

    Fig. Thermostat housing-4.8L, 5.3L and 6.0L engines

  10.  

To install:

  1. Install the thermostat to the water pump housing making sure the spring side is inserted into the engine.
  2.  
  3. Install the bolts.
    1. Tighten the bolts to 11 ft. lbs. (15 Nm).
    2.  

  4.  
  5. Install the radiator outlet hose.
  6.  
  7. Fill the cooling system.
  8.  
  9. Install the air inlet duct.
  10.  
  11. Test the system for leaks.
  12.  


NOTE
Important: The thermostat is not serviceable separately. The water pump inlet and thermostat must be replaced as an assembly.

  1. Drain the cooling system.
  2.  
  3. Loosen the air cleaner outlet duct clamps at the following locations:

    Throttle body
     
    Mass airflow/intake air temperature (MAF/IAT) sensor
     

  4.  
  5. Remove the radiator inlet hose clip from the outlet duct.
  6.  
  7. Remove the air cleaner outlet duct.
  8.  
  9. Reposition the outlet hose clamp at the water pump.
  10.  
  11. Remove the outlet hose from the water pump.
  12.  
  13. Remove the water pump inlet bolts.
  14.  
  15. Remove the water pump inlet and thermostat from the water pump.

    Click image to see an enlarged view

    Fig. Water pump inlet/thermostat assembly location

  16.  

To install:

  1. Install the thermostat and water pump inlet to the water pump.
  2.  
  3. Install the water pump inlet bolts.
  4.  
  5. Tighten the water pump inlet bolts to 11 ft. lbs. (15 Nm).
  6.  
  7. Install the outlet hose to the water pump.
  8.  
  9. Position the outlet hose clamp at the water pump.
    NOTE
    Important: Align the arrow at the throttle body end of the duct with the throttle body attaching stud.

  10.  
  11. Install the air cleaner outlet duct.
  12.  
  13. Install the radiator inlet hose clip to the outlet duct.
  14.  
  15. Tighten the air cleaner outlet duct clamps at the following locations:

    Throttle body
     
    Mass airflow/intake air temperature (MAF/IAT) sensor
     

  16.  
  17. Tighten the air cleaner outlet duct clamp screws to 62 inch lbs. (7 Nm).
  18.  
  19. Fill the cooling system and check for leaks.
  20.  

4.8L, 5.3L, 6.0L & 6.2L Engines



  1. Remove the air inlet duct.
  2.  
  3. Drain the cooling system.
  4.  
  5. Remove the radiator outlet hose.
  6.  
  7. Remove the thermostat housing bolts.
  8.  
  9. Remove the thermostat from the water pump housing.
    NOTE
    The O-ring seal is integral to the thermostat housing



    Click image to see an enlarged view

    Fig. Thermostat housing-4.8L, 5.3L, 6.0L and 6.2L engines

  10.  

To install:

  1. Install the thermostat to the water pump housing making sure the spring side is inserted into the engine.
  2.  
  3. Install the bolts.
    1. Tighten the bolts to 11 ft. lbs. (15 Nm).
    2.  

  4.  
  5. Install the radiator outlet hose.
  6.  
  7. Fill the cooling system.
  8.  
  9. Install the air inlet duct.
  10.  
  11. Test the system for leaks.
  12.  

5.7L & 7.4L Engines



  1. Drain the coolant until the radiator coolant level is below the thermostat.
  2.  
  3. Remove the following items:

    The bolts or studs
     
    The coolant outlet
     
    The thermostat from the housing
     
    The gasket, if needed
     

  4.  
  5. Clean the thermostat housing and the cooling outlet sealing surfaces.

    Click image to see an enlarged view

    Fig. Thermostat mounting-typical

  6.  

To install:

  1. Install the following items:

    The thermostat into the housing
     
    The gasket, if needed
     
    The coolant outlet
     

  2.  
  3. Install the bolts or the studs
  4.  
  5. Tighten the bolts or the studs as follows:

    On 5.7L and 7.4L engines: 21 ft. lbs. (28 Nm).
     
    On 7.4L engines: 27 ft. lbs. (37 Nm).
     

  6.  
  7. Refill the coolant to the cooling system.
  8.  
  9. Start the engine. Run the engine, with the radiator cap removed, until the radiator upper hose becomes hot. This indicates that the thermostat is open.
  10.  
  11. With the engine idling, add coolant to the radiator until the coolant level reaches the bottom of the filler neck.
  12.  
  13. Install the radiator cap to the radiator. Ensure that that the cap arrows line up with the overflow tube.
  14.  
  15. Inspect the cooling system for leaks.
  16.  

6.5L Diesel Engine



  1. Drain the coolant until the radiator coolant level is below the thermostat.
  2.  
  3. Disconnect the radiator inlet hose.
  4.  
  5. Remove the bolt, stud and coolant outlet (4).
  6.  
  7. Remove the gaskets (3).
  8.  
  9. Remove both thermostats (2) from the housing.
  10.  
  11. Clean the sealing surfaces of the thermostat housing and the coolant outlet.

    Click image to see an enlarged view

    Fig. Exploded view of thermostat housing assembly-6.5L Diesel

  12.  

To install:

  1. Install the thermostats (2) into the housing. Replace both thermostats to ensure that the cooling system functions properly.
  2.  
  3. Install the gaskets (3) into position.
  4.  
  5. Install the coolant outlet.
  6.  
  7. Install the bolt and the stud.
    1. Tighten the bolt and the stud to 31 ft. lbs. (42 Nm).
    2.  

  8.  
  9. Connect the radiator inlet hose.
  10.  
  11. Refill the coolant into the cooling system.
  12.  
  13. Start the engine. Run the engine with the radiator cap removed, until the upper radiator hose becomes hot (This indicates that the thermostat is still open).
  14.  
  15. With the engine idling, add coolant to the radiator until the coolant level reaches the bottom of the filler neck.
  16.  
  17. Install the radiator cap to the radiator. Ensure that that the arrows line up with the overflow tube.
  18.  
  19. Inspect the coolant system for leaks.
  20.  

6.5L Engine



  1. Drain the coolant until the radiator coolant level is below the thermostat.
  2.  
  3. Disconnect the radiator inlet hose.
  4.  
  5. Remove the following components:

    The bolt
     
    The stud
     
    The coolant outlet
     

  6.  
  7. Remove the gaskets (2).
  8.  
  9. Remove the thermostats (2) from the housing.
  10.  
  11. Clean the sealing surfaces of the thermostat housing and the coolant outlet.

    Click image to see an enlarged view

    Fig. Thermostats and housing-6.5L engine

  12.  

To install:

  1. Install the thermostats (2) into the housing. Replace both thermostats to ensure that the cooling system functions properly.
  2.  
  3. Install the gaskets (2) into position.
  4.  
  5. Install the coolant outlet.
  6.  
  7. Install the bolt and the stud.
  8.  
  9. Tighten the bolt and the stud to 31 ft. lbs. (42 Nm).
  10.  
  11. Connect the radiator inlet hose.
  12.  
  13. Refill the coolant into the cooling system.
  14.  
  15. Start the engine. Run the engine with the radiator cap removed, until the upper radiator hose becomes hot. This indicates that the thermostat is open.
  16.  
  17. With the engine idling, add coolant to the radiator until the coolant level reaches the bottom of the filler neck.
  18.  
  19. Install the radiator cap to the radiator. Ensure that that the arrows line up with the overflow tube.
  20.  
  21. Inspect the cooling system for leaks.
  22.  

6.6L Diesel Engine



  1. Drain the engine coolant.
  2.  
  3. Remove the water outlet tube.
  4.  
  5. Remove the bolt for the fuel line bracket.
  6.  
  7. Remove the 4 bolts retaining the thermostat housing cover.
  8.  
  9. Remove the 2 thermostats with the seals.

    Click image to see an enlarged view

    Fig. Exploded view thermostat housing assembly-6.6L Engine

  10.  

To install:

  1. Install the 2 thermostats with the seals to the thermostat housing. The rear thermostat (4) has 2 vent valves. Install with the vent valves towards the rear of engine.

    Click image to see an enlarged view

    Fig. View of thermostats in thermostat housing-6.6L engine

  2.  
  3. Install the thermostat housing cover.
    1. Tighten the thermostat housing cover bolts to 15 ft. lbs. (21 Nm).
    2.  

  4.  
  5. Install the fuel line bracket bolt.
    1. Tighten the fuel line bracket and bolt to 15 ft. lbs. (21 Nm).
    2.  

  6.  
  7. Install the water outlet tube.
  8.  
  9. Fill the engine coolant.
  10.  
  11. With the engine idling, add coolant to the radiator until the coolant level reaches the bottom of the filler neck.
  12.  
  13. Install the radiator cap to the radiator.
  14.  
  15. Inspect the coolant system for leaks.
  16.  

8.1L Engine



  1. Drain the cooling system.
  2.  
  3. Reposition the inlet hose clamp at the water outlet.
  4.  
  5. Remove the inlet hose from the water outlet.
  6.  
  7. Remove the water outlet bolts (2).
  8.  
  9. Remove the water outlet (1).
  10.  
  11. Remove the thermostat (3).
  12.  

To install:

Click image to see an enlarged view

Fig. Thermostat assembly-8.1L engine

  1. Install the thermostat (3).
  2.  
  3. Install the water outlet (1).
  4.  
  5. Install the water outlet bolts (2).
    1. Tighten the bolts to 22 ft. lbs. (30 Nm).
    2.  

  6.  
  7. Install the inlet hose to the water outlet.
  8.  
  9. Position the inlet hose clamp at the water outlet.
  10.  
  11. Fill the cooling system.
  12.  
  13. With the engine idling, add coolant to the radiator until the coolant level reaches the bottom of the filler neck.
  14.  
  15. Install the radiator cap to the radiator.
  16.  
  17. Inspect the coolant system for leaks.
  18.  

  1. Drain the cooling system.
  2.  
  3. Reposition the inlet hose clamp at the water outlet.
  4.  
  5. Remove the inlet hose from the water outlet.
  6.  
  7. Remove the water outlet bolts.
  8.  
  9. Remove the water outlet.
  10.  
  11. Remove the thermostat.

    Click image to see an enlarged view

    Fig. Thermostat location-8.1L engine



    Click image to see an enlarged view

    Fig. Detail of thermostat installation

  12.  
  13. Install the thermostat.
  14.  
  15. Install the water outlet.
  16.  
  17. Install the water outlet bolts and tighten to 22 ft. lbs. (30 Nm).
  18.  
  19. Install the inlet hose to the water outlet.
  20.  
  21. Position the inlet hose clamp at the water outlet.
  22.  
  23. Fill the cooling system and check for leaks.
  24.  

  1. Drain the cooling system.
  2.  
  3. Reposition the inlet hose clamp at the water outlet.
  4.  
  5. Remove the inlet hose from the water outlet.
  6.  
  7. Remove the water outlet bolts (2).
  8.  
  9. Remove the water outlet (1).
  10.  
  11. Remove the thermostat (3).
  12.  

To install:

Click image to see an enlarged view

Fig. Thermostat assembly-8.1L engines

  1. Install the thermostat (3).
  2.  
  3. Install the water outlet (1).
  4.  
  5. Install the water outlet bolts (2).
    1. Tighten the bolts to 22 ft. lbs. (30 Nm).
    2.  

  6.  
  7. Install the inlet hose to the water outlet.
  8.  
  9. Position the inlet hose clamp at the water outlet.
  10.  
  11. Fill the cooling system.
  12.  
  13. With the engine idling, add coolant to the radiator until the coolant level reaches the bottom of the filler neck.
  14.  
  15. Install the radiator cap to the radiator.
  16.  
  17. Inspect the coolant system for leaks.
  18.  

 
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