GM Service Manual Online
For 1990-2009 cars only

Removal Procedure

  1. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.

  2. Object Number: 231131  Size: SH
  3. Remove the exhaust muffler front flange bolts.

  4. Object Number: 231156  Size: SH
  5. Remove the hanger insulator retainers from the entire exhaust system support rods.
  6. With the aid of a helper, remove the hanger insulators from the support rods and remove the rear section of the exhaust system.

  7. Object Number: 231206  Size: SH
  8. Remove the pre and post oxygen sensor electrical connectors.

  9. Object Number: 231136  Size: SH
  10. Remove the exhaust manifold pipe nuts from the exhaust manifold studs.

  11. Object Number: 159595  Size: SH
  12. Remove the catalytic converter support bracket bolts (1) from the catalytic converter support bracket (2) and remove the catalytic converters.

Installation Procedure


    Object Number: 231136  Size: SH
  1. Install a new exhaust gasket to the catalytic converter/exhaust manifold flange.
  2. 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 catalytic converter to the exhaust manifold and secure with the fasteners.
  4. Do not tighten the fasteners at this time.


    Object Number: 159595  Size: SH
  5. Install the catalytic converters to the catalytic converter support bracket (2) and secure with the support bracket bolts (1).
  6. Do not tighten the support bracket bolts (1) at this time.

  7. Connect the pre and post catalytic converter electrical connections.

  8. Object Number: 231151  Size: SH
  9. With the aid of a helper, raise the rear section of the exhaust system into place and install the hanger insulators to the support rods at the mufflers.

  10. Object Number: 231159  Size: SH
  11. Install the hanger insulators to the support rods at the resonator.

  12. Object Number: 231156  Size: SH
  13. Install the exhaust hanger insulator retainers to the entire exhaust system.

  14. Object Number: 231131  Size: SH
  15. Install the exhaust muffler front flange bolts.
  16. Do not tighten the bolts at this time.

  17. Check all exhaust system clearances. Refer to Exhaust System Clearances
  18. Tighten

    1. Tighten the exhaust muffler front flange bolts to 40 N·m (30 lb ft).
    2. Tighten the exhaust manifold pipe nuts to 25 N·m (18 lb ft).
    3. Tighten the catalytic converter support bracket bolts to 20 N·m (15 lb ft).
  19. Recheck clearances and operate the exhaust system to inspect for leaks.
  20. Lower the vehicle.