Catalytic Converter Replacement - Right Side

Catalytic Converter Replacement - Right Side (LZ4 - Gas, 6 Cyl, 3.5L, SFI, V6, Offset Bore)

Tools Required

J 39194-B Heated Oxygen Sensor Wrench


Removal Procedure

Notice: The oxygen sensor uses a permanently attached pigtail and connector. Do not remove the pigtail from the oxygen sensor. Damage to or removal of the pigtail connector could affect proper operation of the oxygen sensor.


Notice: The use of excessive force may damage the threads in the exhaust manifold/pipe.


Important: The in-line connector and louvered end must be kept clear of grease, dirt or other contaminants. Avoid using cleaning solvents of any type. DO NOT drop or roughly handle the HO2S.



Important: The HO2S may be difficult to remove when the engine temperature is less than 48°C (120°F).







1. Remove the muffler assembly. Refer to Muffler Replacement (LAT, LZ4) (Service and Repair).
2. Remove the rear stabilizer shaft. Refer to Stabilizer Shaft Replacement (Rear Suspension).
3. Remove the connector position assurance (CPA) retainer (3).
4. Disconnect the lower right heated oxygen sensor (HO2S) electrical connector from the engine wiring harness electrical connector (2).




5. Remove the lower right HO2S (2) using the J 39194-B.




6. Remove the left (front) catalytic converter to right (rear) catalytic converter nuts (3).
7. Remove the right (rear) catalytic converter bolt (5) and nuts (1) at the exhaust manifold.
8. Remove the right catalytic converter (2).
9. Remove and discard the gasket (6).
10. Inspect the catalytic converter-to-exhaust manifold flange.

* Service Limit: 0.7 mm (0.028 in) max.
* Standard: 0.7 mm (0.028 in) max.





Installation Procedure





1. Install a NEW gasket (6) to the catalytic converter.
2. Install the right (rear) catalytic converter (2).

Notice: Refer to Fastener Notice (Fastener Notice).

3. Install the right (rear) catalytic converter bolt (5) and nuts (1) at the exhaust manifold.

Tighten the bolt/nuts to 45 N.m (33 lb ft).

4. Install the left (front) catalytic converter to right (rear) catalytic converter nuts (3).

Tighten the nuts to 25 N.m (18 lb ft).






Important: A special anti-seize compound is used on the HO2S threads. The compound consists of graphite suspended in fluid and glass beads. The graphite will burn away, but the glass beads will remain, making the sensor easier to remove. New or service sensors will already have the compound applied to the threads. If a sensor is removed from an engine and is to be reinstalled, the threads must have anti-seize compound applied before the reinstallation.


5. If reinstalling the old HO2S, coat the threads with anti-seize compound GM P/N 12377953 or equivalent.
6. Install the lower right HO2S (2) using the J 39194-B.

Tighten the sensor to 42 N.m (31 lb ft).





7. Connect the lower right HO2S electrical connector to the engine wiring harness electrical connector (2).
8. Install the CPA retainer (3).
9. Install the rear stabilizer shaft. Refer to Stabilizer Shaft Replacement (Rear Suspension).
10. Install the muffler assembly. Refer to Muffler Replacement (LAT, LZ4) (Service and Repair).