GM Service Manual Online
For 1990-2009 cars only

Catalytic Converter Replacement 3.4L

Removal Procedure

  1. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
  2. Disconnect oxygen sensor wiring harness.
  3. Support the 3-way catalytic converter.

  4. Object Number: 25271  Size: SH
  5. Remove the intermediate pipe from the 3-way catalytic converter.

  6. Object Number: 25280  Size: SH
  7. Remove the exhaust manifold pipe assembly from the exhaust manifold.
  8. Remove the exhaust manifold seal and the 3-way catalytic converter seal.
  9. If replacing catalytic converter, remove oxygen sensor.
  10. Clean the flange surfaces.

Installation Procedure


    Object Number: 25280  Size: SH
  1. Install the exhaust manifold seal and the 3-way catalytic converter seal.
  2. If removed oxygen sensor, install oxygen sensor.
  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.

  4. Install the exhaust manifold pipe assembly to the exhaust manifold.
  5. Tighten
    Tighten the nuts to 45 N·m (33 lb ft).


    Object Number: 25271  Size: SH
  6. Install the intermediate pipe to the 3-way catalytic converter.
  7. Tighten
    Tighten the bolts to 34 N·m (25 lb ft).

  8. Connect oxygen sensor wiring harness.
  9. Lower the vehicle.