Catalytic Converter: Service and Repair

Catalytic Converter Replacement (RPO L26)
Removal Procedure

Caution: Refer to Exhaust Service Caution.

Caution: Refer to Protective Goggles and Gloves Caution.





1. Remove the oxygen sensor wiring harness heat shield.
2. Disconnect the engine harness electrical connector from the heated oxygen sensor (HO2S).





3. Remove the HO2S.





4. Remove the muffler to catalytic converter nuts.

5. Notice: Refer to Flex Decoupler Notice.

Position the exhaust system rearward, enough to allow the studs located in the catalytic converter to clear the exhaust system.
6. Remove and discard the catalytic converter to muffler gasket.





7. Remove the catalytic converter to exhaust manifold nuts.
8. Remove the catalytic converter from the exhaust manifold.
9. Remove and discard the catalytic converter to manifold gasket.

Installation Procedure





1. Notice: Refer to Exhaust System Inspection Notice.

Install a NEW catalytic converter to manifold gasket over the manifold studs.
2. Install the catalytic converter to the exhaust manifold.

3. Notice: Refer to Fastener Notice.

Install the catalytic converter to exhaust manifold nuts.
Tighten the nuts to 40 Nm (30 ft. lbs.).





4. Install a NEW catalytic converter to muffler gasket over the catalytic converter studs.

5. Notice: Refer to Flex Decoupler Notice.

Position the exhaust system until the flange is over the catalytic converter studs.
6. Install the muffler to catalytic converter nuts.
Tighten the nuts to 25 Nm (18 ft. lbs.).





7. Important: A special anti-seize compound is used on the HO2S threads. The compound consists of liquid graphite and glass beads. The graphite tends to burn away, but the glass beads remain, making the sensor easier to remove. New, or service replacement sensors already have the compound applied to the threads. If the sensor is removed from an exhaust component and if for any reason the sensor is to be reinstalled, the threads must have anti-seize compound applied before the reinstallation.

If reinstalling the old sensor, coat the threads with anti-seize compound GM P/N 12377953, or equivalent.
8. Install the HO2S.
Tighten the sensor to 42 Nm (31 ft. lbs.).





9. Connect the engine harness electrical connector to the HO2S.
10. Install the oxygen sensor wiring harness heat shield.