GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Oldsmobile 🢒 1998 🢒 Intrigue 🢒 General Information 🢒 General Information 🢒 Catalytic Converter Replacement

Removal Procedure
  1. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
  2. Disconnect the heated oxygen sensor (HO2S) wiring harness connector and retainers.

    3. Notice: To prevent internal damage to the flexible coupling of the catalytic converter assembly, the converter must be supported. The vertical movement at the rear of the catalytic converter assembly must not exceed 6 degrees up or down.

  3. Suitably support the exhaust system.

    4. Object Number: 289494 Size: SH
  4. Remove the catalytic converter bolts from the three-way catalytic converter pipe flange.
  5. Remove the catalytic converter gasket.

    6. Object Number: 107763 Size: SH
  6. Remove the right (rear) exhaust manifold pipe stud nuts from the exhaust manifold pipe studs.
  7. Remove the three-way catalytic converter.
  8. Remove the exhaust manifold pipe gasket.

    9. Object Number: 289489 Size: SH
  9. Remove the heated oxygen sensor (HO2S). Refer to Heated Oxygen Sensor Replacement in Engine Controls - 3.8L.

Installation Procedure

    Object Number: 289489 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.

  1. Install the heated oxygen sensor (HO2S). Refer to Heated Oxygen Sensor Replacement in Engine Controls - 3.8L.

    2. Object Number: 107763 Size: SH
  2. Install a new exhaust manifold pipe gasket.

    3. Notice: To prevent internal damage to the flexible coupling of the catalytic converter assembly, the converter must be supported. The vertical movement at the rear of the catalytic converter assembly must not exceed 6 degrees up or down.

  3. Install the three-way catalytic converter.
  4. Install the right (rear) exhaust manifold pipe nuts to the exhaust manifold pipe studs.

    5. Tighten
    Tighten the right (rear) exhaust manifold pipe stud nuts to 35 N·m (26 lb ft).


    Object Number: 289494 Size: SH
  5. Install a new catalytic converter gasket.
  6. Install the catalytic converter bolts through the three-way catalytic converter pipe flange.

    7. Tighten
    Tighten the catalytic converter bolts to 45 N·m (33 lb ft).

  7. Remove the support from the exhaust system.
  8. Connect the heated oxygen sensor (HO2S) wiring harness connector and retainers.
  9. Lower the vehicle.
  10. Inspect for exhaust system leaks and underbody contact.