GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 1997 🢒 Express 🢒 Engine 🢒 Engine Exhaust 🢒 Catalytic Converter Replacement

Removal Procedure
  1. Raise the vehicle and support the vehicle with safety stands. Refer to General Vehicle Lifting and Jacking in General Information.

    2. Object Number: 160895 Size: SH
  2. Disconnect the oxygen sensor (O2S) electrical connection.

    3. Object Number: 78428 Size: SH
  3. Remove the nuts and the seals from the exhaust manifold pipes.

    4. Object Number: 160906 Size: SH
  4. On the 4.3L and 5.0L with a 135 inch wheelbase (6100 GVW), remove the clamp from the front of the muffler.

    5. Object Number: 160914 Size: SH
  5. On the 5.7L and the 7.4L with a 135 inch wheelbase (6100 GVW), remove the clamps from the front of the muffler.

    6. Object Number: 160910 Size: SH
  6. On the 4.3L and the 6.5L diesel with a 155 inch wheelbase (below 8600 GVW), remove the clamp from the front of the muffler.

    7. Object Number: 160923 Size: SH
  7. On the 5.7L and the 7.4L with a 155 inch wheelbase (below 8600 GVW), remove the clamps from the front of the muffler.

    8. Object Number: 160928 Size: SH
  8. On the 5.7L with a 155 inch wheelbase (below 8600 GVW), remove the clamp from the front of the muffler.
  9. Remove the retaining nuts from the exhaust flange.

    10. Object Number: 160938 Size: SH
  10. On the 5.7L with a 155 inch wheelbase (above 8600 GVW), remove the clamp from the front of the muffler.
  11. Remove the retaining nuts from the exhaust flange.

    12. Object Number: 160937 Size: SH
  12. On the 5.7L and the 7.4L cutaway and RV remove the clamp from the front of the muffler.
  13. Remove the retaining nuts from the exhaust flange.

    14. Object Number: 160896 Size: SH
  14. Remove the exhaust hangers as necessary.
  15. Remove the catalytic converter from the vehicle.
  16. Remove the oxygen sensors as necessary.

Installation Procedure
  1. Install the oxygen sensors as necessary.
  2. Apply sealer GM P/N 9985020, or equivalent, to the slip joint connections.
  3. Install the catalytic converter assembly into the front muffler pipe.

    4. Object Number: 160896 Size: SH
  4. Install the exhaust hangers as necessary.

    5. Object Number: 160937 Size: SH
  5. On the 5.7L and the 7.4L cutaway and RV install the new retaining nuts to the exhaust flange.
    6. • Do not tighten the flange.
  6. Install the new clamp to the front of the muffler.
    7. • Do not tighten the clamp.

    Object Number: 160938 Size: SH
  7. On the 5.7L with a 155 inch Wheelbase (above 8600 GVW) install the new retaining nuts to the exhaust flange.
    8. • Do not tighten the flange.
  8. Install the new clamp to the front of the muffler.
    9. • Do not tighten the clamp.

    Object Number: 160928 Size: SH
  9. On the 5.7L with a 155 inch wheelbase (below 8600 GVW), install the new retaining nuts to the exhaust flange.
    10. • Do not tighten the flange.
  10. Install the new clamp to the front of the muffler.
    11. • Do not tighten the clamp.

    Object Number: 160923 Size: SH
  11. On the 5.7L and the 7.4L with a 155 inch wheelbase (below 8600 GVW), install the new clamps to the front of the muffler.
    12. • Do not tighten the clamp.

    Object Number: 160910 Size: SH
  12. On the 4.3L and the 6.5L diesel with a 155 inch wheelbase (below 8600 GVW), install the new clamp to the muffler.
    13. • Do not tighten the clamp.

    Object Number: 160914 Size: SH
  13. On the 5.7L and the 7.4L with a 135 inch wheelbase (6100 GVW), install the new clamps to the front of the muffler.
    14. • Do not tighten the clamps.

    Object Number: 160906 Size: SH
  14. On the 4.3L and 5.0L with a 135 inch wheelbase (6100 GVW), install the new clamp to the front of the muffler.
    15. • Do not tighten the clamp.

    Object Number: 78428 Size: SH
  15. Install the new seal and nuts to the exhaust manifold studs.

    16. Tighten
    Tighten the exhaust manifold nuts to 65 N·m (48 lb ft)

    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.

    .

    Tighten
    Verify that the exhaust system is properly aligned and tighten all the exhaust pipe clamps to 70 N·m (52 lb ft).

    Tighten
    Tighten the exhaust flange retaining nuts to the muffler to 48 N·m (35 lb ft).


    Object Number: 160895 Size: SH
  16. Connect the oxygen sensor (O2S) electrical connection.
  17. Verify the exhaust system for proper clearance and the alignment of all components.
  18. Lower the vehicle.