GM Service Manual Online
For 1990-2009 cars only

Intake Manifold Replacement Upper

Removal Procedure

Important: This engine uses a sequential multiport fuel injection system. Connect the injector wiring harness connectors to their appropriate fuel injector or exhaust emissions and engine performance may be seriously affected. For the correct injector wiring harness connector-to-fuel injector connection procedure, refer to Engine Controls.

  1. Disconnect the battery ground (negative) cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.
  2. Remove the throttle body assembly and the accelerator controls cable bracket. Refer to Throttle Body Assembly Replacement in Engine Controls.
  3. Disconnect the left hand spark plug wires. Refer to Spark Plug Wire Harness Replacement in Engine Electrical.
  4. Disconnect the wiring harness attachment clips.
  5. • Camshaft position (CMP) sensor wiring harness.
    • Left hand spark plug wire harness.
    • Engine wiring harness.
  6. Remove the ignition coil bracket with the coils, the purge solenoid and the vacuum canister solenoid. Refer to Ignition Control Module Replacement in Engine Controls.

  7. Object Number: 248103  Size: SH
  8. Disconnect the vacuum hose at the manifold air pressure (MAP) sensor and upper intake manifold.
  9. Remove the manifold air pressure (MAP) sensor and the bracket. Refer to Manifold Absolute Pressure Sensor Replacement in Engine Controls.

  10. Object Number: 612770  Size: SH
  11. Disconnect the emission control vacuum harness.
  12. Disconnect the vacuum hose connections from the upper intake manifold.
  13. • Vacuum booster hose
    • Heater and air conditioning vacuum source hose
    • Fuel pressure regulator
  14. Remove the generator brace. Refer to Generator Brace Replacement in Engine Electrical.

  15. Object Number: 543289  Size: SH
  16. Remove the exhaust gas recirculation (EGR) valve and pipe. Refer to EGR Valve Replacement in Engine Controls.

  17. Object Number: 371638  Size: SH
  18. Remove the upper intake manifold bolts and studs.
  19. Remove the upper intake manifold.

  20. Object Number: 96379  Size: SH
  21. Remove the upper intake manifold gaskets.
  22. Clean the seal surfaces on the manifold with degreaser.

Installation Procedure


    Object Number: 96379  Size: SH
  1. Install the upper intake manifold gaskets.
  2. Install the upper intake manifold.
  3. Loosely install the upper intake manifold bolts and studs.
  4. 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.

  5. Install the upper intake manifold bolts and studs.
  6. Tighten
    Tighten the upper intake manifold bolts and studs to 25 N·m (18 lb ft).


    Object Number: 543289  Size: SH
  7. Install the exhaust gas recirculation (EGR) valve. Refer to EGR Valve Replacement in Engine Controls.
  8. Install the generator brace. Refer to Generator Brace Replacement in Engine Electrical.
  9. Connect the vacuum hose connections to the upper intake manifold.
  10. • Vacuum booster hose
    • Heater and air conditioning vacuum source hose
    • Fuel pressure regulator

    Object Number: 612770  Size: SH
  11. Connect the emission control vacuum harness.
  12. Install the manifold air pressure (MAP) sensor and bracket. Refer to Manifold Absolute Pressure Sensor Replacement in Engine Controls.

  13. Object Number: 248103  Size: SH
  14. Connect the vacuum hose at the manifold air pressure (MAP) sensor and the upper intake manifold.
  15. Install the ignition coil bracket with the coils, the purge solenoid and the vacuum canister solenoid. Refer to Ignition Control Module Replacement in Engine Controls.
  16. Connect the wiring harness attachment clips.
  17. • Camshaft position (CMP) sensor wiring harness
    • Left (front) spark plug wire harness
    • Engine wiring harness
  18. Connect the left hand spark plug wires. Refer to Spark Plug Wire Harness Replacement in Engine Electrical.
  19. Install the throttle body assembly and the accelerator controls cable bracket. Refer to Throttle Body Assembly Replacement in Engine Controls.
  20. Connect the battery ground (negative) cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.

Intake Manifold Replacement Lower

Removal Procedure

Important: This engine uses a sequential multiport fuel injection system. Injector wiring harness connectors must be connected to their appropriate fuel injector or exhaust emissions and engine performance may be seriously affected. For the correct injector wiring harness connector-to-fuel injector connection procedure, refer to Engine Controls.

  1. Disconnect the battery ground (negative) cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.
  2. Drain the engine coolant. Refer to Cooling System Draining and Filling in Engine Cooling.
  3. Remove the upper intake manifold. Refer to Intake Manifold Replacement .
  4. Remove the generator. Refer to Generator Replacement in Engine Electrical.
  5. Remove the left hand valve rocker arm cover. Refer to Valve Rocker Arm Cover Replacement .
  6. Remove the right hand valve rocker arm cover. Refer to Valve Rocker Arm Cover Replacement .

  7. Object Number: 190517  Size: SH
  8. Disconnect the engine coolant temperature (ECT) wiring harness Refer to Engine Coolant Temperature Sensor Replacement in Engine Controls.

  9. Object Number: 190518  Size: SH
  10. Disconnect and remove the fuel injector wiring harness. Refer to Fuel Injection Fuel Rail Assembly Replacement in Engine Controls.
  11. Disconnect and remove the manifold air pressure (MAP) wiring harness. Refer to Manifold Absolute Pressure Sensor Replacement in Engine Controls.

  12. Object Number: 190512  Size: SH
  13. Remove the fuel pipe clip bolt.

  14. Object Number: 190511  Size: SH
  15. Remove the fuel pipe clip.

  16. Object Number: 190514  Size: SH
  17. Disconnect the fuel feed pipe from the fuel injector rail. Refer to Fuel Injection Fuel Rail Assembly Replacement in Engine Controls.

  18. Object Number: 190513  Size: SH
  19. Disconnect the fuel return pipe from the fuel injector rail. Refer to Fuel Injection Fuel Rail Assembly Replacement in Engine Controls.

  20. Object Number: 190516  Size: SH
  21. Remove the fuel injector rail. Refer to Fuel Injection Fuel Rail Assembly Replacement in Engine Controls.
  22. Remove the power steering pump from the front engine cover and reposition aside. Refer to Power Steering Pump Replacement in Power Steering.

  23. Object Number: 371640  Size: SH
  24. Disconnect the heater inlet pipe with heater hose from the lower intake manifold and reposition for access. Refer to Heater Inlet Pipe Replacement in HVAC.
  25. Disconnect the radiator inlet hose from the engine. Refer to Radiator Inlet Hose Replacement in Engine Cooling.

  26. Object Number: 540710  Size: SH
  27. Disconnect the thermostat bypass hose from the thermostat bypass pipe and lower intake manifold pipe.

  28. Object Number: 54281  Size: SH
  29. Remove the lower intake manifold bolts.
  30. Remove the lower intake manifold.

  31. Object Number: 61820  Size: SH
  32. Remove the lower intake manifold gaskets and seals.
  33. Clean the lower intake manifold gasket and seal surfaces on the cylinder heads and the engine block.
  34. Clean the gasket and seal surfaces on the lower intake manifold with degreaser.
  35. Remove all the loose RTV sealer.

  36. Object Number: 190519  Size: SH
  37. Remove the engine coolant temperature (ECT) sensor. Refer to Engine Coolant Temperature Sensor Replacement in Engine Controls.

  38. Object Number: 190520  Size: SH
  39. Remove the water outlet bolts.
  40. Remove the water outlet.

  41. Object Number: 190521  Size: SH
  42. Remove the thermostat. Refer to Engine Coolant Thermostat Replacement in Engine Cooling.

Installation Procedure


    Object Number: 190521  Size: SH
  1. Install the thermostat. Refer to Engine Coolant Thermostat Replacement in Engine Cooling.

  2. Object Number: 190520  Size: SH
  3. Install the water outlet.
  4. 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.

  5. Install the water outlet bolts.
  6. Tighten
    Tighten the water outlet bolts to 25 N·m (18 lb ft).


    Object Number: 190519  Size: SH
  7. Install the engine coolant temperature (ECT) sensor. Refer to Engine Coolant Temperature Sensor Replacement in Engine Controls.

  8. Object Number: 61820  Size: SH
  9. Apply 8-12 mm (0.08-0.11 in) bead of RTV Sealer, or equivalent, on each ridge where front and rear of the lower intake manifold contact the engine block (1).
  10. Install the lower intake manifold gaskets.

  11. Object Number: 54281  Size: SH
  12. Install the lower intake manifold.
  13. Apply sealant, GM P/N 12345382 to the threads of the bolts.
  14. Notice: An oil leak may result if the vertical bolts are not tightened before the diagonal bolts.

  15. Hand tighten the vertical lower intake manifold bolts.
  16. Hand tighten the diagonal lower intake manifold bolts.

  17. Object Number: 190523  Size: SH
  18. Install the lower intake manifold bolts.
  19. Tighten

    1. Tighten the vertical lower intake manifold bolts (1) to 13 N·m (115 lb in).
    2. Tighten the diagonal lower intake manifold bolts (2) to 13 N·m (115 lb in).

    Object Number: 540710  Size: SH
  20. Connect the thermostat bypass hose to the thermostat bypass pipe and lower intake manifold pipe.
  21. Connect the radiator inlet hose to the engine. Refer to Radiator Inlet Hose Replacement in Engine Cooling.

  22. Object Number: 371640  Size: SH
  23. Connect the heater inlet pipe and heater hose to the lower intake manifold. Refer to Heater Inlet Pipe Replacement in HVAC.
  24. Install the power steering pump to the front engine cover. Refer to Power Steering Pump Replacement in Power Steering.

  25. Object Number: 190516  Size: SH
  26. Install the fuel injector rail. Refer to Fuel Injection Fuel Rail Assembly Replacement in Engine Controls.

  27. Object Number: 190513  Size: SH
  28. Connect the fuel return pipe to the fuel injector rail. Refer to Fuel Injection Fuel Rail Assembly Replacement in Engine Controls.

  29. Object Number: 190514  Size: SH
  30. Connect the fuel feed pipe to the fuel injector rail. Refer to Fuel Injection Fuel Rail Assembly Replacement in Engine Controls.

  31. Object Number: 190511  Size: SH
  32. Install the fuel pipe clip.

  33. Object Number: 190512  Size: SH
  34. Install the fuel pipe clip bolt.
  35. Tighten
    Tighten the fuel pipe clip bolt to 8 N·m (71 lb in).


    Object Number: 190518  Size: SH
  36. Install and connect the fuel injector wiring harness. Refer to Fuel Injection Fuel Rail Assembly Replacement in Engine Controls.
  37. Install and connect the manifold air pressure (MAP) wiring harness. Refer to Fuel Injection Fuel Rail Assembly Replacement in Engine Controls.

  38. Object Number: 190517  Size: SH
  39. Connect the engine coolant temperature (ECT) wiring harness. Refer to Engine Coolant Temperature Sensor Replacement in Engine Controls.
  40. Install the right hand valve rocker arm cover. Refer to Valve Rocker Arm Cover Replacement .
  41. Install the left hand valve rocker arm cover. Refer to Valve Rocker Arm Cover Replacement .
  42. Install the Generator. Refer to Generator Replacement in Engine Electrical.
  43. Install the upper intake manifold. Refer to Intake Manifold Replacement .
  44. Fill the cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.
  45. Connect the battery ground (negative) cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.