GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Oldsmobile 🢒 1998 🢒 Achieva 🢒 Engine 🢒 Engine Controls - 3.1L 🢒 Intake Manifold Replacement

Intake Manifold Replacement Lower

Removal Procedure

    Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

  1. Disconnect the negative battery cable.
  2. Depressurize the fuel system. Refer to Fuel Pressure Relief in Engine Controls - 3.1L.
  3. Remove the top half of the air cleaner assembly.
  4. Drain and recover the cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.

    5. Object Number: 187076 Size: SH
  5. Remove the EGR pipe from the exhaust manifold.
  6. Remove the drive belt. Refer to Drive Belt Replacement .
  7. Remove the brake vacuum pipe at the plenum.
  8. Remove the power steering lines at the generator bracket.
  9. Remove the generator. Refer to Generator Replacement in Engine Electrical.

    10. Object Number: 63926 Size: SH
  10. Remove the secondary ignition wires from the spark plugs.
  11. Remove the secondary ignition wires from the harness at the plenum.

    12. Object Number: 187080 Size: SH
  12. Remove the following components at the same time:
    13. • Electronic ignition coil and module assembly
    • EVAP canister purge solenoid
  13. Remove the following upper engine wiring connectors:
    14. • Throttle Position (TP) sensor
    • IAC sensor
    • Injector harness
    • Engine Coolant Temperature (ECT) sensor
    • MAP sensor
    • Camshaft Position (CMP) sensor

    Object Number: 187081 Size: SH
  14. Remove the following vacuum lines:
    15. • Vacuum Modulator
    • Fuel Pressure Regulator
    • PCV

    Object Number: 54360 Size: SH
  15. Remove the MAP sensor from the upper intake manifold.

    16. Object Number: 54358 Size: SH
  16. Remove the upper intake manifold bolts.
  17. Remove the upper intake manifold.

    18. Object Number: 54696 Size: SH
  18. Remove the fuel lines at the fuel rail and the bracket.
  19. Install the J 28467-360 .
  20. Remove the engine mount assembly. Refer to Engine Mount Replacement .
  21. Remove the power steering mounting bolts. Support the pump aside. Refer to Power Steering Pump Replacement in Pwer Steering System.

    22. Object Number: 187060 Size: SH
  22. Remove the heater inlet pipe from the coolant outlet housing.

    23. Object Number: 187084 Size: SH
  23. Remove the heater by-pass at the coolant pump and the cylinder head.
  24. Remove the radiator hose at the heater outlet housing.
  25. Remove the heater outlet housing.
  26. Remove both of the valve rocker covers. Refer to Valve Rocker Arm Cover Replacement .

    27. Important: Retain the washers in the same orientation on the center bolts.


    Object Number: 54281 Size: SH
  27. Remove the lower intake manifold bolts.
  28. Remove the lower intake manifold.
  29. Loosen the rocker arms.

    30. Object Number: 54392 Size: SH

    Object Number: 187046 Size: SH

    Important:  Keep the pushrods in order. The pushrods must be installed in the original position.

  30. Remove the pushrods.

    31. Object Number: 61187 Size: SH
  31. Remove the intake gasket.
  32. Inspect the flatness of the inlet flanges.
  33. Clean the following items:
    34. • Gasket material from the mating surfaces
    • Excess RTV sealant from the front and the rear ridges of the cylinder
    • Block
    • Sealing surfaces with degreaser

Installation Procedure

    Important: All gasket-mating surfaces need to be free of oil, and foreign material. Use GM P/N 12346139 (Canadian P/N 10953463) or equivalent to clean surfaces.


    Object Number: 61187 Size: SH
  1. Install the intake manifold gasket.

    2. Object Number: 187046 Size: SH
  2. Install the pushrods.
    3. 2.1. Install the pushrods in their original location.
    2.2. Coat the ends of the pushrods with prelube GM P/N  1052356, or the equivalent.
    2.3. Intake pushrods are 144 mm (5.75 in).
    2.4. Exhaust pushrods are 152.5 mm (6.0 in).
    2.5. Ensure that the pushrods seat in the lifter.

    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.

  3. Install the rocker arm bolts.

    4. Tighten
    Tighten the bolts to 10 N·m (89 lb in) +30 degrees.


    Object Number: 843417 Size: SH

    Important: All gasket-mating surfaces need to be free of oil, and foreign material. Use GM P/N 12346139 (Canadian P/N 10953463) or equivalent to clean surfaces.

  4. With gaskets in place apply a small drop 8-10 mm (0.31-0.39 in) of RTV sealer GM P/N 12346141 (Canadian P/N 10953433) or equivalent to the 4 corners of the intake manifold to block joint (1).
  5. Connect the 2 small drops with a bead of RTV sealer that is between 8-10 mm (0.31-0.39 in) wide and 3.0-5.0 mm (0.12-0.20 in) thick (2).
  6. Install the lower intake manifold.

    7. Object Number: 187067 Size: SH

    Important: All lower intake manifold bolts need to be cleaned, free of any foreign material, and reused only if new bolts are unavailable. Use GM P/N 12345382 (Canadian P/N 10953489) or equivalent and apply to the old intake manifold bolt threads.

    Important: Manufacturer recommends the center bolts be fully torqued before the diagonal bolts to assure proper seal ability.

    Important: Lower intake manifold bolts in location 6 and 7 should be torqued to specification using a crows foot type tool.

  7. Install the lower intake manifold bolts.

    8. Tighten

    1. Tighten the lower intake manifold bolts in sequence to 7 N·m (62 lb in) on the first pass.
    2. Tighten the lower intake manifold bolts (1, 2, 3, 4) in sequence to 13 N·m (115 lb in) on the final pass.
    3. Tighten the lower intake manifold bolts (5, 6, 7, 8) in sequence to 25 N·m (18 lb ft) on the final pass.
  8. Install the water outlet housing.
  9. Install the radiator hose to the thermostat housing.

    10. Object Number: 187060 Size: SH
  10. Install the heater inlet pipe to the thermostat housing.

    11. Object Number: 862487 Size: SH

    Important: Do not press on the fuel pressure regulator valve when installing the fuel injector rail assembly.

  11. Install the fuel injector rail assembly.
    12. 11.1. Install the fuel injector O-rings using GM P/N 12345616, (Canadian P/N 993182) or equivalent.
    11.2. Install the injector nozzles into the lower intake manifold injector bores.
    11.3. Press on the injector rail using the palms of both hands until the injectors are fully seated.
  12. Install the fuel injector rail bolts.

    13. Tighten
    Tighten the fuel injector rail bolts to 10 N·m (89 lb in).


    Object Number: 187065 Size: SH
  13. Install the fuel feed and return pipe retaining clip.
  14. Install the fuel feed and return pipe retaining clip bolt.

    15. Tighten
    Tighten the fuel feed and return pipe retaining clip bolt to 8 N·m (71 lb in).


    Object Number: 54358 Size: SH
  15. Install the upper intake manifold. Refer to Intake Manifold Replacement .
  16. Install the valve rocker covers. Refer to Valve Rocker Arm Cover Replacement .

Intake Manifold Replacement Upper

Removal Procedure

Tools Required

J 28467-360 Engine Support Fixture.

    Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

  1. Disconnect the negative battery cable.
  2. Depressurize the fuel system. Refer to Fuel Pressure Relief in Engine Controls - 3.1L.
  3. Remove the top half of the air cleaner assembly.
  4. Drain and recover the cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.

    5. Object Number: 54670 Size: SH
  5. Remove the EGR pipe from the exhaust manifold.
  6. Remove the drive belt. Refer to Drive Belt Replacement .
  7. Remove the brake vacuum pipe at the plenum.
  8. Remove the power steering lines at the generator bracket.
  9. Remove the generator. Refer to Generator Replacement .

    10. Object Number: 63926 Size: SH
  10. Remove the secondary ignition wires from the spark plugs.
  11. Remove the secondary ignition wires from the harness at the plenum.
  12. Remove the following components at the same time:
    13. • Electronic ignition coil and module assembly
    • EVAP canister purge solenoid
  13. Remove the following upper engine wiring connectors:
    14. • Throttle Position (TP) sensor
    • IAC sensor
    • Injector harness
    • Engine Coolant Temperature (ECT) sensor
    • MAP sensor
    • Camshaft Position (CMP) sensor
  14. Remove the following vacuum lines:
    15. • Vacuum Modulator
    • Fuel Pressure Regulator
    • PCV
  15. Remove the MAP sensor from the upper intake manifold.

    16. Object Number: 54358 Size: SH
  16. Remove the upper intake manifold bolts.
  17. Remove the upper intake manifold.

Installation Procedure

    Object Number: 54358 Size: SH
  1. Install the upper intake manifold.

    2. 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.

  2. Install the upper intake manifold bolts.

    3. Tighten
    Tighten the bolts to 25 N·m (18 lb ft).

  3. Install the MAP sensor.
  4. Connect the following vacuum lines:
    5. • Vacuum Modulator
    • Fuel Pressure Regulator
    • PCV
  5. Install the following upper engine wiring connectors:
    6. • Throttle Position (TP) sensor
    • IAC sensor
    • Injector harness
    • Engine Coolant Temperature (ECT) sensor
    • MAP sensor
    • Camshaft Position (CMP) sensor
  6. Install the following components:
    7. • EVAP canister purge solenoid
    • Electronic ignition coil and module assembly
  7. Install the generator. Refer to Generator Replacement in Engine Electrical.
  8. Install the power steering line at the generator bracket.
  9. Install the drive belt. Refer to Drive Belt Replacement .

    10. Object Number: 63926 Size: SH
  10. Install the secondary ignition wires to the spark plugs.
  11. Install the secondary ignition wires to the harness at the plenum.

    12. Object Number: 54670 Size: SH
  12. Install the EGR pipe to the exhaust manifold.
  13. Install the following items to the throttle body:
    14. • Throttle body cable
    • Cruise control cable
  14. Install the top half of the air cleaner assembly.
  15. Install the brake vacuum pipe.
  16. Install the cables to the throttle body.
  17. Fill the cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.
  18. Connect the negative battery cable.
  19. Inspect for proper fluid levels.
  20. Check for leaks.