GM Service Manual Online
For 1990-2009 cars only

Catalytic Converter Replacement Gasoline Below 8600 lb GVWR

Removal Procedure

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

  2. Object Number: 160895  Size: SH
  3. Disconnect the oxygen sensor electrical connections.

  4. Object Number: 412920  Size: SH
  5. Remove the nuts from the Y-pipe flat flange.
  6. Remove the Y-pipe and the catalytic converter assembly.

  7. Object Number: 78428  Size: SH
  8. Remove the nuts and the flange seals from the Y-pipe and the exhaust manifold.

Installation Procedure


    Object Number: 78428  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 new flange seals and the new nuts to the exhaust manifold.
  2. Tighten
    Tighten the nuts to 65 N·m (48 lb ft).


    Object Number: 412920  Size: SH
  3. Position the Y-pipe and the catalytic converter assembly to the flat flange.
  4. Install the nuts to the flat flange studs.
  5. Tighten
    Tighten the nuts to 64 N·m (47 lb ft).


    Object Number: 160895  Size: SH
  6. Connect the oxygen sensor electrical connections.
  7. Check for clearance and alignment.
  8. Lower the vehicle.

Catalytic Converter Replacement Gasoline Above 8600 lb GVWR

Removal Procedure

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

  2. Object Number: 160895  Size: SH
  3. Disconnect the oxygen sensor electrical connections.

  4. Object Number: 107621  Size: SH
  5. Remove the nuts from the Y-pipe flat flange.

  6. Object Number: 78428  Size: SH
  7. Remove the nuts and the flange seals from the Y-pipe and the exhaust manifold.

  8. Object Number: 107621  Size: SH
  9. Remove the Y-pipe and the catalytic converter assembly.
  10. Remove the muffler and the catalytic converter assembly.

Installation Procedure


    Object Number: 78428  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 flange seals and the nuts to the exhaust manifold.
  2. Tighten
    Tighten the nuts to 65 N·m (48 lb ft).

  3. Install the muffler and the catalytic converter assembly.

  4. Object Number: 107621  Size: SH
  5. Position the Y-pipe and the catalytic converter assembly to the flat flange.
  6. Install the nuts to the flat flange studs.
  7. Tighten
    Tighten the nuts to 64 N·m (47 lb ft).


    Object Number: 160895  Size: SH
  8. Connect the oxygen sensor electrical connections.
  9. Check for clearance and alignment.
  10. Lower the vehicle.

Catalytic Converter Replacement Diesel

Removal Procedure

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

  2. Object Number: 164372  Size: SH
  3. Remove the front exhaust pipe flange stud nuts from the front of the catalytic converter assembly.
  4. Remove the clamp from the exhaust manifold pipe.


    Object Number: 164370  Size: SH
  5. Remove the U-bolt from the rear of the catalytic converter assembly.

  6. Object Number: 440823  Size: SH
  7. Remove the catalytic converter from the muffler assembly.

Installation Procedure


    Object Number: 440823  Size: SH
  1. Install a new flange gasket and the catalytic converter to the front exhaust pipe flange studs.

  2. Object Number: 164372  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.

  3. Install the nuts to the exhaust pipe flange studs.
  4. Tighten
    Tighten the nuts to 64 N·m (47 lb ft).


    Object Number: 164370  Size: SH
  5. Install a new U-bolt to the rear of the catalytic converter.
  6. Tighten
    Tighten the nuts to 42 N·m (31 lb ft).

    Install the clamp to the exhaust manifold pipe.

    Tighten
    Tighten the nut to 12 N·m ( 106 lb in).

  7. Check for clearance and alignment.
  8. Lower the vehicle.

Catalytic Converter Replacement Gas, Export

Removal Procedure

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

  2. Object Number: 412921  Size: SH
  3. Remove the nuts from the Y-pipe flat flange.
  4. Remove the muffler and the catalytic converter assembly.

  5. Object Number: 78428  Size: SH
  6. Remove the nuts, studs, and flange seals from the Y-pipe and the exhaust manifold.

Installation Procedure


    Object Number: 78428  Size: SH
  1. Install the new flange seals.
  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 new studs.
  4. Tighten
    Tighten the studs to 22 N·m (16 lb ft).

  5. Install the new nuts connecting the Y-pipe, catalytic converter assembly to the exhaust manifold.
  6. Tighten
    Tighten the nuts to 64 N·m (47 lb ft).


    Object Number: 412921  Size: SH
  7. Position the Y-pipe and the catalytic converter assembly to the flat flange.
  8. Install the nuts to the flat flange studs.
  9. Tighten
    Tighten the nuts to 64 N·m (47 lb ft).

  10. Check for clearance and alignment.
  11. Lower the vehicle.