Catalytic Converter: Service and Repair

WARNING: THE NORMAL OPERATING TEMPERATURE OF THE EXHAUST SYSTEM IS VERY HIGH. THEREFORE, NEVER ATTEMPT TO SERVICE ANY PART OF THE EXHAUST SYSTEM UNTIL IT IS COOLED. SPECIAL CARE SHOULD BE TAKEN WHEN WORKING NEAR THE CATALYTIC CONVERTER. THE TEMPERATURE OF THE CONVERTER RISES TO A HIGH LEVEL AFTER A SHORT PERIOD OF ENGINE OPERATION TIME.

WARNING: IF TORCHES ARE USED WHEN WORKING ON THE EXHAUST SYSTEM, DO NOT ALLOW THE FLAME NEAR THE FUEL LINES.

CAUTION: When servicing exhaust system components, disconnect the oxygen sensor connector(s). Allowing the exhaust system to hang by the oxygen sensor harness will damage the wiring and/or sensor.

REMOVAL
(1) Raise and support the vehicle.

Exhaust Pipe With Catalytic Converter-2.5L Engine:

Exhaust Pipe With Catalytic Converter-4.0L Engine:

(2) Saturate the studs and nuts with a rust penetrant. Allow 5 minutes for penetration.
(3) Remove the oxygen sensors from the exhaust pipe and the catalytic converter.
(4) Disconnect the exhaust pipe from the engine exhaust manifold. Discard the seal (4.0L engine, only).
(5) Support the transmission and remove the rear crossmember.
(6) Remove the clamp from the catalytic converter and muffler connection.
(7) Heat the catalytic converter and muffler connection with an oxyacetylene torch until the metal becomes cherry red.
(8) While the metal is still cherry red, twist the muffler assembly back and forth to separate it from the catalytic converter.

INSTALLATION

(1) Assemble catalytic converter and muffler loosely to permit proper alignment of all parts.
(2) Use a new clamp and tighten the nut to 48 Nm (35 ft. lbs.) torque.
(3) Connect the exhaust pipe to the engine exhaust manifold. Install a new seal between the exhaust manifold and the exhaust pipe (4.0L engine, only). Tighten the nuts to 31 Nm (23 ft. lbs.) torque.
(4) Install the rear crossmember. Tighten the crossmember-to-sill bolts to 41 Nm (30 ft. lbs.) torque. Remove the support from the transmission
(5) Coat the oxygen sensors with anti-seize compound. Install the sensors and tighten the nut to 30 Nm (22 ft. lbs.) torque.
(6) Lower the vehicle.
(7) Start the engine and inspect for exhaust leaks and exhaust system contact with the body panels. Adjust the alignment, if needed.