GM Service Manual Online
For 1990-2009 cars only

Engine Coolant Thermostat Housing Replacement RPO L61

Removal Procedure


    Object Number: 1631385  Size: SH
  1. Drain the cooling system. Refer to Cooling System Draining and Filling
  2. Remove the air cleaner assembly. Refer to Air Cleaner Assembly Replacement .
  3. Remove the air cleaner bracket nuts.
  4. Remove the air cleaner bracket.

  5. Object Number: 1631387  Size: SH
  6. Remove the exhaust heat shield studs (2).
  7. Remove the exhaust heat shield (1).

  8. Object Number: 1212666  Size: SH

    Important: A drain has been provided at the bottom of the water pump for engine block coolant drainage.

  9. Drain the coolant from the engine block at the water pump drain. After the coolant has drained, tighten the drain bolt.
  10. Lower the vehicle.

  11. Object Number: 1625483  Size: SH
  12. If equipped with a automatic transaxle, perform the following steps, disconnect the engine coolant temperature (ECT) sensor electrical connector (1).
  13. Disconnect the heated oxygen sensor (HO2S) electrical connector clip from the thermostat housing.

  14. Object Number: 1625486  Size: SH
  15. If equipped with a manual transaxle, disconnect the ECT sensor electrical connector (1).

  16. Object Number: 1713085  Size: SH
  17. Remove the ECT sensor.

  18. Object Number: 1713958  Size: SH
  19. Reposition the radiator outlet hose clamp at the thermostat housing.
  20. Remove the radiator outlet hose from the thermostat housing.

  21. Object Number: 1625419  Size: SH
  22. Reposition the heater inlet and outlet hose clamps at the thermostat housing pipes.
  23. Disconnect the heater inlet and outlet hoses from the thermostat housing pipes.
  24. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .

  25. Object Number: 1713067  Size: SH
  26. Remove the thermostat housing bolts.
  27. Important: Twist the water transfer pipe while pulling in order to remove it from the water pump.

  28. Remove the thermostat housing from the vehicle.
  29. Remove the water transfer pipe from the thermostat housing, if necessary.
  30. Remove and discard the water transfer pipe O-ring seals, if necessary.

  31. Object Number: 1713064  Size: SH
  32. Remove the thermostat housing cover bolts and cover, if necessary.
  33. Remove the thermostat, if necessary.
  34. Remove and discard the thermostat housing O-ring seal, if necessary.
  35. Remove all debris and thread sealant from the engine coolant temperature sensor and bolt holes if the housing is being re-used.

Installation Procedure


    Object Number: 1713064  Size: SH
  1. Install a NEW thermostat housing cover O-ring seal into the recess groove.
  2. Install the thermostat, if necessary.
  3. Notice: Refer to Fastener Notice in the Preface section.

  4. Install the thermostat housing cover bolts, if necessary.
  5. Tighten
    Tighten the bolts to 10 N·m (89 lb in).

  6. Install a NEW thermostat housing to engine gasket onto the thermostat housing.
  7. Load the thermostat housing assembly into position.

  8. Object Number: 1713067  Size: SH

    Important: The water feed pipe seals can be lightly lubricated with coolant to aid during installation.

  9. Install NEW O-ring seals onto the water feed pipe.
  10. Important: Lubricate the O-rings with coolant ONLY.

  11. Install the water feed pipe into the thermostat housing aligning locator tab.
  12. Align the water pipe to water pump.
  13. Seat the water feed O-ring seal by pushing inward toward the water pump. Take care not to tear or damage the O-ring.
  14. Position the thermostat housing against the engine.
  15. Install the thermostat housing bolts.
  16. Tighten
    Tighten the bolts to 10 N·m (89 lb in).

  17. Lower the vehicle.

  18. Object Number: 1625419  Size: SH
  19. Connect the heater inlet and outlet hoses to the thermostat housing pipes.
  20. Position the heater inlet and outlet hose clamps at the thermostat housing pipes.

  21. Object Number: 1713958  Size: SH
  22. Install the radiator outlet hose to the thermostat housing.
  23. Position the radiator outlet hose clamp at the thermostat housing.

  24. Object Number: 1713085  Size: SH
  25. If reinstalling the old sensor, coat the threads with sealant. Refer to Adhesives, Fluids, Lubricants, and Sealers .
  26. Install the ECT sensor.
  27. Tighten
    Tighten the sensor to 20 N·m (15 lb ft).


    Object Number: 1625486  Size: SH
  28. If equipped with a manual transaxle, connect the ECT sensor electrical connector (1).

  29. Object Number: 1625483  Size: SH
  30. If equipped with a automatic transaxle, perform the following steps, connect the ECT sensor electrical connector (1).
  31. Connect the HO2S electrical connector clip to the thermostat housing.

  32. Object Number: 1212666  Size: SH

    Important: The vehicle must be level when filling the cooling system.

  33. Verify the drain valves at the radiator and water pump are closed.
  34. Fill the cooling system. Refer to Cooling System Draining and Filling .
  35. Lower the vehicle.

  36. Object Number: 1631387  Size: SH
  37. Install the exhaust heat shield (2).
  38. Install the exhaust heat shield studs (1).
  39. Tighten
    Tighten the studs to 22 N·m (16 lb ft).


    Object Number: 1631385  Size: SH
  40. Install the air cleaner bracket.
  41. Install the air cleaner bracket nuts.
  42. Tighten
    Tighten the nuts to 10 N·m (89 lb in).

  43. Install the air cleaner assembly. Refer to Air Cleaner Assembly Replacement .
  44. Verify the repair and inspect for any leaks.

Engine Coolant Thermostat Housing Replacement RPO LE5

Removal Procedure


    Object Number: 1631385  Size: SH
  1. Drain the cooling system. Refer to Cooling System Draining and Filling .
  2. Remove the air cleaner assembly. Refer to Air Cleaner Assembly Replacement .
  3. Remove the air cleaner bracket nuts.
  4. Remove the air cleaner bracket.

  5. Object Number: 1631387  Size: SH
  6. Remove the exhaust heat shield studs (2).
  7. Remove the exhaust heat shield (1).

  8. Object Number: 1212666  Size: SH

    Important: A drain has been provided at the bottom of the water pump for engine block coolant drainage.

  9. Drain the coolant from the engine block at the water pump drain. After the coolant has drained, tighten the drain bolt.
  10. Lower the vehicle.

  11. Object Number: 1625483  Size: SH
  12. If equipped with a automatic transaxle, perform the following steps, disconnect the engine coolant temperature (ECT) sensor electrical connector (1).
  13. Disconnect the heated oxygen sensor (HO2S) electrical connector clip from the thermostat housing.

  14. Object Number: 1625486  Size: SH
  15. If equipped with a manual transaxle, disconnect the ECT sensor electrical connector (1).

  16. Object Number: 1713085  Size: SH
  17. Remove the ECT sensor.

  18. Object Number: 1631168  Size: SH
  19. If the vehicle is equipped with a engine oil cooler perform the following steps, otherwise proceed to step 17.
  20. Reposition the oil cooler outlet hose clamp at the thermostat housing.
  21. Remove the oil cooler outlet hose from the thermostat housing.

  22. Object Number: 1631170  Size: SH
  23. Reposition the radiator outlet hose clamp (1) at the thermostat housing.
  24. Remove the radiator outlet hose from the thermostat housing. Proceed to step 19.

  25. Object Number: 1713958  Size: SH
  26. If the vehicle is not equipped with a engine oil cooler, reposition the radiator outlet hose clamp at the thermostat housing.
  27. Remove the radiator outlet hose from the thermostat housing.

  28. Object Number: 1625419  Size: SH
  29. Reposition the heater inlet and outlet hose clamps at the thermostat housing pipes.
  30. Disconnect the heater inlet and outlet hoses from the thermostat housing pipes.
  31. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .

  32. Object Number: 1713067  Size: SH
  33. Remove the thermostat housing bolts.
  34. Important: Twist the water transfer pipe while pulling in order to remove it from the water pump.

  35. Remove the thermostat housing from the vehicle.
  36. Remove the water transfer pipe from the thermostat housing, if necessary.
  37. Remove and discard the water transfer pipe O-ring seals, if necessary.

  38. Object Number: 1713064  Size: SH
  39. Remove the thermostat housing cover bolts and cover, if necessary.
  40. Remove the thermostat, if necessary.
  41. Remove and discard the thermostat housing O-ring seal, if necessary.
  42. Remove all debris and thread sealant from the engine coolant temperature sensor and bolt holes if the housing is being re-used.

Installation Procedure


    Object Number: 1713064  Size: SH
  1. Install a NEW thermostat housing cover O-ring seal into the recess groove.
  2. Install the thermostat, if necessary.
  3. Notice: Refer to Fastener Notice in the Preface section.

  4. Install the thermostat housing cover bolts, if necessary.
  5. Tighten
    Tighten the bolts to 10 N·m (89 lb in).

  6. Install a NEW thermostat housing to engine gasket onto the thermostat housing.
  7. Load the thermostat housing assembly into position.

  8. Object Number: 1713067  Size: SH

    Important: The water feed pipe seals can be lightly lubricated with coolant to aid during installation.

  9. Install NEW O-ring seals onto the water feed pipe.
  10. Important: Lubricate the O-rings with coolant ONLY.

  11. Install the water feed pipe into the thermostat housing aligning locator tab.
  12. Align the water pipe to water pump.
  13. Seat the water feed O-ring seal by pushing inward toward the water pump. Take care not to tear or damage the O-ring.
  14. Position the thermostat housing against the engine.
  15. Install the thermostat housing bolts.
  16. Tighten
    Tighten the bolts to 10 N·m (89 lb in).

  17. Lower the vehicle.

  18. Object Number: 1625419  Size: SH
  19. Connect the heater inlet and outlet hoses to the thermostat housing pipes.
  20. Position the heater inlet and outlet hose clamps at the thermostat housing pipes.

  21. Object Number: 1713958  Size: SH
  22. If the vehicle is not equipped with a engine oil cooler perform the following steps, otherwise proceed to step 18.
  23. Install the radiator outlet hose to the thermostat housing.
  24. Position the radiator outlet hose clamp at the thermostat housing. Proceed to step 22.

  25. Object Number: 1631170  Size: SH
  26. If the vehicle is equipped with a engine oil cooler, install the radiator outlet hose to the thermostat housing.
  27. Position the radiator outlet hose clamp (1) at the thermostat housing.

  28. Object Number: 1631168  Size: SH
  29. Install the oil cooler outlet hose to the thermostat housing.
  30. Position the oil cooler outlet hose clamp at the thermostat housing.

  31. Object Number: 1713085  Size: SH
  32. If reinstalling the old ECT sensor, coat the threads with sealant. Refer to Adhesives, Fluids, Lubricants, and Sealers .
  33. Install the ECT sensor.
  34. Tighten
    Tighten the sensor to 20 N·m (15 lb ft).


    Object Number: 1625486  Size: SH
  35. If equipped with a manual transaxle, connect the ECT sensor electrical connector (1).

  36. Object Number: 1625483  Size: SH
  37. If equipped with a automatic transaxle, perform the following steps, connect the ECT sensor electrical connector (1).
  38. Connect the HO2S electrical connector clip to the thermostat housing.

  39. Object Number: 1212666  Size: SH

    Important: The vehicle must be level when filling the cooling system.

  40. Verify the drain valves at the radiator and water pump are closed.
  41. Fill the cooling system. Refer to Cooling System Draining and Filling .
  42. Lower the vehicle.

  43. Object Number: 1631387  Size: SH
  44. Install the exhaust heat shield (1).
  45. Install the exhaust heat shield studs (2).
  46. Tighten
    Tighten the studs to 22 N·m (16 lb ft).


    Object Number: 1631385  Size: SH
  47. Install the air cleaner bracket.
  48. Install the air cleaner bracket nuts.
  49. Tighten
    Tighten the nuts to 10 N·m (89 lb in).

  50. Install the air cleaner assembly. Refer to Air Cleaner Assembly Replacement .
  51. Verify the repair and inspect for any leaks.