Catalytic Converter: Service and Repair

Catalytic Converter Replacement (4.3L, 4.8L, and 5.3L Engines)
Removal Procedure





1. Raise and suitably support the vehicle.
2. If equipped, unclip the oxygen sensor connection from the floor reinforcement.
3. Disconnect the oxygen sensor electrical connector.





4. Remove the oxygen sensor clips from the frame.
5. Disconnect the connector position assurance (CPA) retainers.
6. Disconnect the oxygen sensor electrical connectors.





7. Unclip the oxygen sensors electrical connectors from the following:
^ Hose clip
^ Transmission crossmember
8. Disconnect the CPA retainers.
9. Disconnect the oxygen sensor electrical connectors (1, 2).





10. Remove the left exhaust manifold pipe nuts.





11. Remove the right exhaust manifold pipe nuts.





12. Remove the exhaust muffler nuts.
13. Remove the catalytic converter.





14. If necessary, remove the oxygen sensors.

Installation Procedure

Notice: Refer to Fastener Notice in Service Precautions.





1. If necessary, install the oxygen sensors.
1. Apply anti-seize compound GM P/N 12377953 or equivalent to the threads of the old oxygen sensors.
2. Install the oxygen sensors.
Tighten the sensors to 42 Nm (31 ft. lbs.).
2. Install the catalytic convertor.





3. Install NEW exhaust manifold pipe seals to the exhaust manifolds.
4. Install the right exhaust manifold pipe nuts until snug.





5. Install the left exhaust manifold pipe nuts until snug.
6. Tighten the exhaust manifold pipe nuts.
Tighten the nuts to 50 Nm (39 ft. lbs.).





7. Install the exhaust muffler nuts.
Tighten the nuts to 40 Nm (30 ft. lbs.).





8. Connect the oxygen sensor electrical connectors (1, 2).
9. Connect the CPA retainers.
10. Clip the oxygen sensors electrical connectors to the following:
^ Hose clip
^ Transmission crossmember





11. Connect the oxygen sensor electrical connectors.
12. Connect the CPA retainers.
13. Install the clip around the engine harness and the oxygen sensor pigtail.





14. Connect the oxygen sensor electrical connector.
15. If equipped, clip the oxygen sensor connection to the floor reinforcement.
16. Lower the vehicle.