GM Service Manual Online
For 1990-2009 cars only

Thermostat Housing Crossover Replacement LLY/LBZ

Removal Procedure

  1. Remove the radiator fan. Refer to Fan Replacement .
  2. Remove the drive belt tensioner and generator bracket. Refer to Generator Bracket Replacement .
  3. Remove the air conditioning (A/C) and power steering bracket. Refer to Air Conditioning (A/C) Compressor and Power Steering Pump Bracket Replacement .

  4. Object Number: 1728628  Size: SH
  5. Remove the fuel line bolt and position the fuel line aside.

  6. Object Number: 1728627  Size: SH
  7. Compress the clamp and disconnect the turbocharger inlet cooling hose/pipe.

  8. Object Number: 1730413  Size: SH
  9. Remove the oil fill tube bolts and the oil fill tube.
  10. Disconnect the coolant temperature sensor electrical connector.
  11. Remove the exhaust gas recirculation (EGR) coolant pipe. Refer to Exhaust Gas Recirculation Coolant Hoses/Pipes Replacement .

  12. Object Number: 1335434  Size: SH
  13. Remove the fuel pipe bracket bolt.
  14. Disconnect the hose at the thermostat bypass pipe.
  15. Disconnect the radiator inlet hose from the thermostat housing.
  16. Remove the thermostat bypass bolts at the water pump.

  17. Object Number: 1335441  Size: SH
  18. Remove the 8 thermostat housing crossover bolts.
  19. Remove the thermostat housing crossover.

Installation Procedure

  1. Position the thermostat housing crossover.
  2. Notice: Refer to Fastener Notice in the Preface section.


    Object Number: 1335441  Size: SH
  3. Install the 8 thermostat housing crossover bolts.
  4. Tighten
    Tighten the thermostat housing crossover bolts to 25 N·m (18 lb ft).

  5. Install the thermostat bypass bolts to the water pump.
  6. Tighten
    Tighten to 21 N·m (16 lb ft).

  7. Install the radiator inlet hose to the thermostat housing.
  8. Connect the hose to the thermostat bypass pipe.

  9. Object Number: 1335434  Size: SH
  10. Install the fuel pipe bracket bolt.
  11. Tighten
    Tighten the fuel pipe bracket bolt to 25 N·m (18 lb ft).

  12. Install the EGR coolant pipe. Refer to Exhaust Gas Recirculation Coolant Hoses/Pipes Replacement .
  13. Connect the coolant temperature sensor electrical connector.

  14. Object Number: 1730413  Size: SH
  15. Install the oil fill tube bolts and the oil fill tube.
  16. Tighten
    Tighten the oil fill tube bolts to 25 N·m (18 lb ft).


    Object Number: 1728627  Size: SH
  17. Compress the clamp and connect the turbocharger inlet cooling hose/pipe.

  18. Object Number: 1728628  Size: SH
  19. Position the fuel line and install the fuel line bolt.
  20. Install the A/C and power steering bracket. Refer to Air Conditioning (A/C) Compressor and Power Steering Pump Bracket Replacement .
  21. Install the drive belt tensioner and generator bracket. Refer to Generator Bracket Replacement .
  22. Instal the radiator fan. Refer to Fan Replacement .

Thermostat Housing Crossover Replacement LMM

Removal Procedure

  1. Remove the radiator fan. Refer to Fan Replacement.
  2. Remove the drive belt tensioner and generator bracket. Refer to Generator Bracket Replacement.
  3. Remove the air conditioning (A/C) and power steering bracket. Refer to Air Conditioning (A/C) Compressor and Power Steering Pump Bracket Replacement.

  4. Object Number: 1728628  Size: SH
  5. Remove the fuel line bolt and position the fuel line aside.

  6. Object Number: 1728627  Size: SH
  7. Compress the clamp and disconnect the turbocharger inlet cooling hose/pipe.
  8. Remove the oil fill tube. Refer to Oil Filler Tube Replacement.

  9. Object Number: 1865507  Size: SH
  10. Disconnect two coolant temperature sensor electrical connectors (1).
  11. Remove the fuel pipe bracket bolt (2).

  12. Object Number: 1999250  Size: SH
  13. Remove the 8 thermostat housing crossover bolts.
  14. Remove the thermostat housing crossover.
  15. Remove the thermostat housing crossover gasket.

Installation Procedure

  1. Install a NEW thermostat housing crossover gasket.
  2. Position the thermostat housing crossover.
  3. Notice: Refer to Fastener Notice in the Preface section.


    Object Number: 1999250  Size: SH
  4. Install the 8 thermostat housing crossover bolts.
  5. Tighten
    Tighten the thermostat housing crossover bolts to 25 N·m (18 lb ft).


    Object Number: 1865507  Size: SH
  6. Install the fuel pipe bracket bolt.
  7. Tighten
    Tighten the fuel pipe bracket bolt to 25 N·m (18 lb ft).

  8. Connect two coolant temperature sensor electrical connectors (1).
  9. Install the oil fill tube. Refer to Oil Filler Tube Replacement.

  10. Object Number: 1728627  Size: SH
  11. Compress the clamp and connect the turbocharger inlet cooling hose/pipe.

  12. Object Number: 1728628  Size: SH
  13. Position the fuel line and install the fuel line bolt.
  14. Install the A/C and power steering bracket. Refer to Air Conditioning (A/C) Compressor and Power Steering Pump Bracket Replacement.
  15. Install the drive belt tensioner and generator bracket. Refer to Generator Bracket Replacement.
  16. Instal the radiator fan. Refer to Fan Replacement.