GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2003 🢒 Century 🢒 Engine 🢒 Engine Mechanical - 3.1L 🢒 Upper Intake Manifold Replacement

Removal Procedure

    Object Number: 248101 Size: SH
  1. Disconnect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.
  2. Remove the air cleaner intake duct. Refer to Air Cleaner Inlet Duct Replacement in Engine Controls - 3.1L.
  3. Remove the accelerator controls cable bracket with the accelerator control and the cruise control cables. Refer to Accelerator Control Cable Bracket Replacement in Engine Controls - 3.1L.
  4. Remove the vacuum hoses from the following:
    5. • Fuel pressure regulator
    • Evaporative emissions (EVAP) canister purge valve
    • Manifold vacuum source
    • Brake booster to the upper intake manifold
    • Windshield washer system
  5. Disconnect the electrical connectors from the following:
    6. • Exhaust gas recirculation (EGR) valve
    • Mass air flow (MAF) sensor
    • Idle air control (IAC) valve
    • Throttle position (T/P) sensor
    • Evaporative emission (EVAP) canister purge valve
  6. Drain the cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.
  7. Remove the left side spark plug wires from the spark plugs. Refer to Spark Plug Wire Replacement in Engine Controls - 3.1L.
  8. Remove the following wiring harnesses from the retainers:
    9. • Camshaft position (CMP) sensor wiring harness
    • Left side spark plug wire harness
    • Engine wiring harness

    Object Number: 622761 Size: SH
  9. Remove the thermostat bypass pipe coolant hoses (3,4) from the throttle body.
  10. Remove the ignition coil bracket with the coils. Refer to Ignition Coil Replacement in Engine Controls - 3.1L.
  11. Remove the EVAP canister purge valve. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement in Engine Controls - 3.1L.
  12. Remove the manifold absolute pressure (MAP) sensor and the bracket. Refer to Manifold Absolute Pressure Sensor Replacement in Engine Controls - 3.1L.
  13. Remove the exhaust gas recirculation (EGR) valve. Refer to Exhaust Gas Recirculation Valve Replacement in Engine Controls - 3.1L.

    14. Object Number: 813509 Size: SH
  14. Remove the upper intake manifold bolts and the stud.
  15. Remove the upper intake manifold.
  16. Remove the upper intake manifold gaskets.

    17. Object Number: 61827 Size: SH
  17. If replacing the upper intake manifold, remove the throttle body. Refer to Throttle Body Assembly Replacement in Engine Controls - 3.1L.
  18. Clean the upper intake gasket mating surfaces.

Installation Procedure

    Object Number: 61827 Size: SH
  1. If removed, install the throttle body. Refer to Throttle Body Assembly Replacement in Engine Controls - 3.1L.

    2. Object Number: 813509 Size: SH
  2. Install the upper intake manifold gaskets.
  3. Install the upper intake manifold.

    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.

  4. Install the upper intake manifold bolts and the stud.

    5. Tighten
    Tighten the bolts and the stud to 25 N·m (18 lb ft).

  5. Install the EGR valve. Refer to Exhaust Gas Recirculation Valve Replacement in Engine Controls - 3.1L.
  6. Install the MAP sensor bracket and the sensor. Refer to Manifold Absolute Pressure Sensor Replacement in Engine Controls - 3.1L.
  7. Install the EVAP canister purge valve. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement in Engine Controls - 3.1L.
  8. Install the ignition coil bracket with the coils. Refer to Ignition Coil Replacement in Engine Controls - 3.1L.

    9. Object Number: 622761 Size: SH
  9. Install the thermostat bypass pipe coolant hoses (3,4) to the throttle body.
  10. Install the following wiring harnesses to the retainers:
    11. • Engine wiring harness
    • Left side spark plug wire harness
    • Camshaft position (CMP) sensor wiring harness
  11. Install the left side spark plug wires to the spark plugs. Refer to Spark Plug Wire Replacement in Engine Controls - 3.1L.
  12. Connect the electrical connectors to the following:
    13. • Evaporative emission (EVAP) canister purge valve
    • Throttle position (T/P) sensor
    • Idle air control (IAC) valve
    • Mass air flow (MAF) sensor
    • Exhaust gas recirculation (EGR) valve

    Object Number: 248101 Size: SH
  13. Install the vacuum hoses to the following:
    14. • Windshield washer system
    • Brake booster to the upper intake manifold
    • Manifold vacuum source
    • Evaporative emissions (EVAP) canister purge valve
    • Fuel pressure regulator
  14. Install the accelerator controls cable bracket with the accelerator control and the cruise control cables. Refer to Accelerator Control Cable Bracket Replacement in Engine Controls - 3.1L.
  15. Install the air cleaner intake duct. Refer to Air Cleaner Inlet Duct Replacement in Engine Controls - 3.1L.
  16. Connect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.
  17. Fill the cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.