GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2003 🢒 LeSabre 🢒 Engine 🢒 Engine Mechanical - 3.8L 🢒 Upper Intake Manifold Replacement

Removal Procedure
  1. Remove the fuel injector sight shield. Refer to Fuel Injector Sight Shield Replacement .
  2. Disconnect the manifold vacuum source.
  3. Remove the evaporative emission canister purge valve and secure the hoses to the air inlet grill. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement in Engine Controls - 3.8L.
  4. Disconnect the right spark plug wires from the ignition module and position aside.
  5. Remove the MAP sensor. Refer to Manifold Absolute Pressure Sensor Replacement in Engine Controls - 3.8L.

    6. Object Number: 211908 Size: SH
  6. Remove the engine wiring harness heat shield fasteners.
  7. Remove the engine wiring harness heat shield.
  8. Remove the fuel rail mounting bolts and the fuel rail with the injectors. Refer to Fuel Injection Fuel Rail Assembly Replacement in Engine Controls - 3.8L.

    9. Object Number: 203920 Size: SH
  9. Remove the throttle body support bracket bolts.
  10. Remove the throttle body support bracket.
  11. Remove the air cleaner intake duct. Refer to Air Cleaner Inlet Duct Replacement in Engine Controls - 3.8L.

    12. Object Number: 153566 Size: SH
  12. Remove the nuts securing the throttle body to the upper intake manifold.
  13. Remove the throttle body and position aside.
  14. Remove the throttle body gasket.

    15. Object Number: 42225 Size: SH
  15. Remove the upper intake manifold bolts.
  16. Remove the upper intake manifold.
  17. Clean and inspect the upper intake manifold. Refer to Upper Intake Manifold Cleaning and Inspection in Engine Mechanical - 3.8L Unit Repair.
  18. Clean the lower intake manifold mating surface.

Installation Procedure

    Object Number: 42225 Size: SH

    Important: Do not use any sealer on the gasket.

  1. Install the new upper intake manifold gasket.
  2. Position the upper intake manifold to the lower intake manifold.

    3. Object Number: 49828 Size: SH

    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 upper intake manifold bolts.

    4. Tighten
    Tighten the upper intake manifold bolts in sequence (1-10) to 10 N·m (89 lb in).


    Object Number: 153566 Size: SH
  4. Position a new throttle body gasket to the upper intake manifold.
  5. Install the throttle body to the upper intake manifold.
  6. Install the nuts securing the throttle body to the upper intake manifold.

    7. Tighten
    Tighten the throttle body nuts to 10 N·m (89 lb in).

  7. Install the air cleaner intake duct. Refer to Air Cleaner Inlet Duct Replacement in Engine Controls - 3.8L.

    8. Object Number: 203920 Size: SH
  8. Install the throttle body support bracket.
  9. Install the throttle body support bracket bolts.

    10. Tighten
    Tighten the throttle body support bracket bolts to 10 N·m (89 lb in).

  10. Install the fuel rail assembly. Refer to Fuel Injection Fuel Rail Assembly Replacement in Engine Controls - 3.8L.

    11. Object Number: 211908 Size: SH
  11. Install the engine wiring harness heat shield.
  12. Install the engine wiring harness heat shield fasteners.

    13. Tighten
    Tighten the engine wiring harness heat shield fasteners to 10 N·m (89 lb in).

  13. Install the MAP sensor. Refer to Manifold Absolute Pressure Sensor Replacement in Engine Controls - 3.8L.
  14. Connect the right spark plug wires to the ignition module.
  15. Install the evaporative emission canister purge valve. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement in Engine Controls - 3.8L.
  16. Connect the manifold vacuum source.
  17. Install the fuel injector sight shield. Refer to Fuel Injector Sight Shield Replacement .