GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 1998 🢒 Skylark 🢒 Engine 🢒 Engine Controls - 3.1L 🢒 Exhaust Manifold Replacement

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. Remove the top half of the air cleaner assembly. Remove the throttle body duct.

    3. Object Number: 54366 Size: SH
  3. Remove the exhaust crossover heat shield.

    4. Object Number: 54282 Size: SH
  4. Remove the exhaust crossover pipe at the exhaust manifold.
  5. Remove the heated oxygen sensor.

    6. Object Number: 54670 Size: SH
  6. Remove the EGR pipe at the exhaust manifold.
  7. Raise the vehicle. Support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
  8. Remove the transmission oil level indicator and fill tube assembly. Refer to Filler Tube Replacement in Automatic Transaxle - 4T60 - E.
  9. Remove the exhaust pipe from the exhaust manifold.
  10. Remove the exhaust pipe from the converter flange.
  11. Support the converter aside.
  12. Remove the converter heat shield from the vehicle body.

    13. Object Number: 54707 Size: SH
  13. Remove the exhaust manifold heat shield bolts.
  14. Remove the exhaust manifold heat shield.

    15. Object Number: 54301 Size: SH
  15. Remove the exhaust manifold nuts/studs.
  16. Remove the exhaust manifold from the bottom of the vehicle.
  17. Clean the mating surfaces at the cylinder head and at the exhaust manifold.

Installation Procedure

    Object Number: 54301 Size: SH
  1. Install the exhaust manifold gasket.
  2. Install the exhaust manifold. Loosely, install the heat shield at this time.

    3. 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 exhaust manifold nuts/studs.

    4. Tighten
    Tighten the exhaust manifold nuts to 16 N·m (12 lb ft).


    Object Number: 54707 Size: SH
  4. Install the exhaust manifold heat shield.
  5. Install the exhaust manifold heat shield bolts.

    6. Tighten
    Tighten the exhaust manifold heat shield bolts to 10 N·m (89 lb in).

  6. Install the converter heat shield to the body.
  7. Install the exhaust pipe to the converter flange.
  8. Install the exhaust pipe to the exhaust manifold.
  9. Install the transmission oil level indicator and fill tube assembly. Refer to Filler Tube Replacement in Automatic Transaxle - 4T60 - E.
  10. Lower the vehicle.
  11. Install the heated oxygen sensor.

    12. Tighten
    Tighten the oxygen sensor to 42 N·m (31 lb ft).


    Object Number: 54282 Size: SH
  12. Install the exhaust crossover pipe to the exhaust manifolds.

    13. Tighten
    Tighten the exhaust nuts/studs to 25 N·m (18 lb ft).


    Object Number: 54366 Size: SH
  13. Install the exhaust crossover heat shield.

    14. Tighten
    Tighten the exhaust crossover heat shield bolts to 10 N·m (89 lb in).


    Object Number: 54670 Size: SH
  14. Install the EGR pipe to the exhaust manifold.

    15. Tighten
    Tighten the EGR pipe bolt to 25 N·m (18 lb ft).

  15. Install the top half of the air cleaner assembly. Install the throttle body duct.
  16. Connect the negative battery cable.
  17. Check for exhaust leaks.