GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2001 🢒 Regal (China) 🢒 Engine 🢒 Engine Mechanical - 2.5L (LB8) and 3.0L (LW9) 🢒 Lower Intake Manifold Replacement

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.

  1. Disconnect the battery ground (negative) cable. Refer to Battery Negative Cable Disconnect/Connect Procedure in Engine Electrical.
  2. Remove the upper intake manifold. Refer to Intake Manifold Replacement (Upper).
  3. Remove the left valve rocker arm cover. Refer to Valve Rocker Arm Cover Replacement (Left Front).
  4. Remove the right valve rocker arm cover. Refer to Valve Rocker Arm Cover Replacement (Right Rear).

    5. Object Number: 190517 Size: SH
  5. Disconnect the engine coolant temperature (ECT) wiring harness.

    6. Object Number: 190518 Size: SH
  6. Disconnect and remove the fuel injector and manifold air pressure (MAP) wiring harness.

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

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

    9. Object Number: 190514 Size: SH
  9. Disconnect the fuel feed pipe from the fuel injector rail. Refer to Fuel Rail Assembly Replacement in Engine Controls-2.5 L (LB8) and 3.0 L (LW9).

    10. Object Number: 190513 Size: SH
  10. Disconnect the fuel return pipe from the fuel injector rail. Refer to Fuel Rail Assembly Replacement in Engine Controls-2.5 L (LB8) and 3.0 L (LW9).

    11. Object Number: 190516 Size: SH
  11. Remove the fuel injector rail. Refer to Fuel Rail Assembly Replacement in Engine Controls-2.5 L (LB8) and 3.0 L (LW9).
  12. Disconnect the power steering pump from the front engine cover and reposition aside.
  13. Disconnect the heater inlet pipe with heater hose from the lower intake manifold and reposition.
  14. Disconnect the radiator inlet hose from the engine. Refer to Radiator Hose Replacement - Inlet in Engine Cooling.

    15. Object Number: 190522 Size: SH
  15. Disconnect the thermostat bypass hose from the thermostat bypass pipe and lower intake manifold pipe.

    16. Object Number: 54281 Size: SH
  16. Remove the lower intake manifold bolts.
  17. Remove the lower intake manifold.
  18. Remove the valve rocker arms and pushrods. Refer to Valve Rocker Arm and Push Rod Removal.

    19. Object Number: 61820 Size: SH
  19. Remove the lower intake manifold gaskets and seals.
  20. Clean the lower intake manifold gasket and seal surfaces on the cylinder heads and the engine block.
  21. Clean the gasket and seal surfaces on the lower intake manifold with degreaser.
  22. Remove all the loose RTV sealer.

    23. Object Number: 190519 Size: SH
  23. If replacing the lower intake manifold remove the engine coolant temperature (ECT) sensor.

    24. Object Number: 190520 Size: SH
  24. If replacing the lower intake manifold remove the water outlet bolts.
  25. Remove the water outlet.

    26. Object Number: 190521 Size: SH
  26. If replacing the lower intake manifold remove the thermostat.

Installation Procedure

    Object Number: 190521 Size: SH
  1. If removed install the thermostat.

    2. Object Number: 190520 Size: SH
  2. If removed install the water outlet.

    3. Install the water outlet bolts. Refer to Water Outlet Installation.


    Object Number: 190519 Size: SH
  3. If removed install the engine coolant temperature (ECT) sensor.

    4. Tighten
    Tighten the engine coolant temperature (ECT) sensor to 23 N·m (17 lb ft).


    Object Number: 61820 Size: SH
  4. Install the lower intake manifold gaskets.
  5. Install the valve rocker arms and pushrods. Refer to Valve Rocker Arm and Push Rod Installation.

    6. Object Number: 54281 Size: SH
  6. Install the lower intake manifold. Refer to Intake Manifold Installation (Lower) .

    7. Object Number: 190522 Size: SH
  7. Connect the thermostat bypass hose to the thermostat bypass pipe and lower intake manifold pipe.
  8. Connect the radiator inlet hose to the engine. Refer to Radiator Hose Replacement - Inlet in Engine Cooling.
  9. Connect the heater inlet pipe and heater hose to the lower intake manifold.
  10. Install the power steering pump to the front engine cover. Refer to Power Steering Pump Replacement in Power Steering System.

    11. Object Number: 190516 Size: SH
  11. Install the fuel injector rail. Refer to Fuel Rail Assembly Replacement in Engine Controls-2.5 L (LB8) and 3.0 L (LW9).

    12. Object Number: 190513 Size: SH
  12. Connect the fuel return pipe to the fuel injector rail. Refer to Fuel Rail Assembly Replacement in Engine Controls-2.5 L (LB8) and 3.0 L (LW9).

    13. Object Number: 190514 Size: SH
  13. Connect the fuel feed pipe to the fuel injector rail. Refer to Fuel Rail Assembly Replacement in Engine Controls-2.5 L (LB8) and 3.0 L (LW9).

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

    15. Object Number: 190512 Size: SH
  15. Install the fuel pipe clip bolt.

    16. Tighten
    Tighten the fuel pipe clip bolt to 8 N·m (71 lb in).


    Object Number: 190518 Size: SH
  16. Connect the fuel injector and manifold air pressure (MAP) wiring harness.

    17. Object Number: 190517 Size: SH
  17. Connect the engine coolant temperature (ECT) wiring harness.
  18. Install the right valve rocker arm cover. Refer to Valve Rocker Arm Cover Replacement (Right Rear).
  19. Install the left valve rocker arm cover. Refer to Valve Rocker Arm Cover Replacement (Left Front).
  20. Install the upper intake manifold. Refer to Intake Manifold Replacement (Upper).
  21. Connect the battery ground (negative) cable. Refer to Battery Negative Cable Disconnect/Connect Procedure in Engine Electrical.