Catalytic Converter Replacement Utility 4.3L

Caution: Always wear protective goggles and gloves when removing exhaust parts as falling rust and sharp edges from worn exhaust components could result in serious personal injury.

Notice: When jacking or lifting the vehicle from the frame side rails, be certain lift pads do not contact the three-way catalytic converter as damage to the converter will result.

Notice: Replacement of exhaust system parts must be OEM standard to ensure that the vehicle operates as designed.

1. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
2. Remove the transmission support. Refer to Transmission Support Replacement in Frame and Underbody.



3. Disconnect the LH pre-converter heated oxygen sensor (HO2S) electrical connection.



4. Disconnect the RH pre-converter heated oxygen sensor (HO2S) electrical connection.



5. Disconnect the post-converter heated oxygen sensor (HO2S) electrical connection.



6. Remove the muffler to the catalytic converter flange nuts.
7. Remove the muffler from the catalytic converter.



8. Remove the catalytic converter to exhaust manifold flange nuts.



9. Remove the catalytic converter from the rubber catalytic converter hangers.
10. Remove the catalytic converter and gasket from the vehicle.
11. Remove the heated oxygen sensors (HO2S) as necessary.

1. Install the heated oxygen sensors (HO2S) as necessary.
2. Install the catalytic converter and NEW gaskets to the vehicle.
3. Install the catalytic converter to the catalytic converter rubber hangers.




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 catalytic converter to exhaust manifold flange nuts.

Tighten
Tighten the catalytic converter to exhaust manifold nuts to 53 N·m (39 lb ft).




5. Install the muffler and NEW gasket to the catalytic converter.
6. Install the muffler to the catalytic converter flange nuts.

Tighten
Tighten the muffler to the catalytic converter flange nuts to 40 N·m (30 lb ft).




7. Connect the post-converter heated oxygen sensor (HO2S) electrical connection.



8. Connect the RH pre-converter heated oxygen sensor (HO2S) electrical connection.



9. Connect the LH pre-converter heated oxygen sensor (HO2S) electrical connection.
10. Install the transmission support. Refer to Transmission Support Replacement in Frame and Underbody.
11. Lower the vehicle.