Catalytic Converter: Service and Repair

Catalytic Converter Replacement (4.2L Engine)

Removal Procedure

1. Raise the vehicle. Refer to Lifting and Jacking the Vehicle.
2. Remove the heated oxygen sensor (H2OS). Refer to Heated Oxygen Sensor 2 Replacement.




3. Remove the nuts that secure the catalytic converter pipe to the exhaust manifold.
4. Discard the old exhaust seal. Do NOT reuse the seal.




5. Remove the nuts that secure the catalytic converter pipe to the muffler.
6. Remove the transmission mount. Refer to Transmission Mount Replacement (4.2L) Transmission Mount Replacement (5.3L).
7. Remove the catalytic converter pipe from the vehicle.




8. Remove the exhaust hanger from the catalytic converter pipe.

Installation Procedure




1. Install the exhaust hanger to the catalytic converter pipe.
2. Install the catalytic converter pipe to the vehicle.
3. Install the transmission mount. Refer to Transmission Mount Replacement (4.2L) Transmission Mount Replacement (5.3L).
4. Install the converter pipe to the muffler.




Notice: Refer to Fastener Notice.

Important: The exhaust flange nuts must be tightened evenly to align the joint and prevent exhaust leaks.

5. Hand thread both nuts evenly until they contact the exhaust flange.

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

Important: Do NOT reuse the old exhaust seal. ALWAYS replace the exhaust seal to prevent exhaust leaks.




6. Install the converter pipe to the exhaust manifold with a NEW exhaust seal.
7. Hand thread the nuts evenly against the exhaust flange until the pipe is secure.

Tighten the nuts to 50 N.m (37 lb ft).

8. Install the H2OS. Refer to Heated Oxygen Sensor 2 Replacement.
9. Lower the vehicle.