Jeep Cherokee (XJ): Removal and installation

Jeep Cherokee (XJ) 1984 - 2001 Service Manual > Exhaust system > Removal and installation

Exhaust pipe

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.

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.

(2) Saturate the bolts and nuts with Mopart Rust Penetrant (Fig. 7) (Fig. 8). Allow 5 minutes for penetration.

Fig. 7 Exhaust Pipe Removal-2.5L

1 - NUT
2 - TRANSMISSION SUPPORT
3 - MINI CATALYTIC CONVERTER
4 - EXHAUST PIPE
5 - EXHAUST MANIFOLD

(3) Disconnect the oxygen sensor connector(s).

(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 nuts and clamp. To remove the exhaust pipe from the catalytic converter, apply heat until the metal becomes cherry red. Disconnect the exhaust pipe from the catalytic converter.

Remove the exhaust pipe.

Fig. 8 Exhaust Pipe Removal-4.0L

1 - NUT
2 - EXHAUST MANIFOLD
3 - TRANSMISSION SUPPORT
4 - EXHAUST PIPE
5 - MINI CATALYTIC CONVERTER
6 - BOLT

INSTALLATION

(1) Assemble exhaust pipe to manifold and catalytic converter loosely to permit proper alignment of all parts.

(2) Use a new clamp and tighten the nuts to 61 N·m (45 ft. lbs.) torque.

(3) Connect the exhaust pipe to the engine exhaust manifold (Fig. 7) (Fig. 8). Install a new seal between the exhaust manifold and the exhaust pipe (4.0L engine only). Tighten the nuts to 31 N·m (23 ft. lbs.) torque.

(4) Install the rear crossmember. Install and tighten the four (4) crossmember to rear mount nuts to 22 N·m (16 ft. lbs.) Install and tighten the crossmember to sill bolts to 42 N·m (31 ft. lbs.) torque.

Remove the support from the transmission.

(5) Carefully coat the threads on the oxygen sensor( s) with anti-seize compound. Install the sensor and tighten the nut to 27 N·m (20 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.

Catalytic converter

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.

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.

(2) Remove the clamps from the catalytic converter and muffler connection (Fig. 9).

(3) Disconnect and remove the oxygen sensor from the catalytic converter.

(4) Heat the catalytic converter and muffler connection with an oxyacetylene torch until the metal becomes cherry red.

(5) While the metal is still cherry red, twist the muffler assembly back and forth to separate it from the catalytic converter.

(6) Disconnect the exhaust pipe from the catalytic converter (Fig. 9). If needed, heat up the pipes to separate.

INSTALLATION

(1) Connect the catalytic converter to the exhaust pipe and the muffler/tailpipe assy. (Fig. 9). Use a new clamp and tighten the nuts to 61 N·m (45 ft. lbs.) torque.

(2) Install the muffler onto the catalytic converter until the alignment tab is inserted into the alignment slot.

(3) Install a new clamp at the muffler and catalytic converter connection (Fig. 9). Tighten the clamp nut to 61 N·m (45 ft. lbs.) torque.

(4) Coat the oxygen sensor with anti-seize compound.

Install the sensor and tighten the nut to 27 N·m (20 ft. lbs.) torque.

(5) Lower the vehicle.

(6) Start the engine and inspect for exhaust leaks and exhaust system contact with the body panels.

Adjust the alignment, if needed.

Muffler and tailpipe

All original equipment exhaust systems are manufactured with the exhaust tailpipe welded to the muffler.

Service replacement mufflers and exhaust tailpipes are either clamped together or welded together.

Fig. 9 Catalytic Converter to Muffler and Exhaust Pipe Connection

1 - EXHAUST CLAMP ASSEMBLY
2 - OXYGEN SENSOR
3 - MUFFLER
4 - CATALYTIC CONVERTER
5 - EXHAUST PIPE

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

CAUTION: When servicing exhaust system components, disconnect the oxygen sensor connector.

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.

(2) Disconnect front tailpipe hanger from the insulator (Fig. 10).

(3) Remove the front exhaust clamp from the catalytic converter and muffler connection (Fig. 11).

(4) Heat the catalytic converter-to-muffler connection with an oxyacetylene torch until the metal becomes cherry red.

(5) While the metal is still cherry red, remove the exhaust muffler/tailpipe assembly from the catalytic converter.

(6) Slide the muffler/tailpipe assy. rearward and out of the rear exhaust tailpipe mounting bracket (Fig. 11).

Fig. 10 Front Exhaust Tailpipe Hanger

1 - MUFFLER
2 - INSULATOR
3 - TAILPIPE
4 - FRONT TAILPIPE HANGER

(7) Remove the muffler from the exhaust tailpipe:

To remove an original equipment exhaust muffler/ tailpipe combination, cut the exhaust tailpipe close to the muffler. Collapse the part remaining in the muffler and remove.
To remove a service exhaust tailpipe/muffler combination, apply heat until the metal becomes cherry red. Remove the exhaust tailpipe/muffler clamp and twist the exhaust tailpipe out of the muffler.

INSTALLATION

(1) Install the muffler onto the catalytic converter.

Install the clamp and tighten the nut finger tight.

(2) Install the exhaust tailpipe into the rear of the muffler.

(3) Install the exhaust tailpipe/muffler assembly on the rear exhaust tailpipe mounting bracket. Make sure that the exhaust tailpipe has sufficient clearance from the floor pan.

(4) Install front tailpipe hanger into the insulator (Fig. 10).

(5) Align the muffler and tighten the nuts on the muffler-to-catalytic converter clamp to 61 N·m (45 ft.

lbs.) torque (Fig. 11).

(6) Align the tailpipe and install a new clamp at the muffler to tailpipe connection.

(7) Tighten the muffler to tailpipe clamp to 61 N·m (45 ft. lbs.) (8) Lower the vehicle.

Fig. 11 Muffler/Tailpipe Removal and Installation

1 - MUFFLER AND TAIL PIPE HANGER
2 - CLAMP
3 - CATALYTIC CONVERTER
4 - MUFFLER AND TAIL PIPE ASSEMBLY
5 - TAIL PIPE
6 - TAIL PIPE HANGER CLAMP

(9) Start the engine and inspect for exhaust leaks and exhaust system contact with the body panels.

Adjust the alignment, if needed.

Heat shields

REMOVAL

(1) Raise and support the vehicle.

(2) Remove the screws and/or nuts holding the heat shields to the frame and/or floor pan (Fig. 12).

Fig. 12 Heat Shield Removal/Installation

1 - BOLTS
2 - MUFFLER HEAT SHIEL
3 - NUTS
4 - FLOOR PAN

(3) When removing muffler heat shield, the muffler front support bracket must be removed first.

(4) Slide the shields out around the exhaust system.

INSTALLATION

(1) Position the heat shields to the floor pan or the frame and install the screws and/or nuts.

(2) Tighten the nuts and/or screws to 45 N·m (33 ft. lbs.) (Fig. 12).

(3) Lower the vehicle.

Diagnosis and testing

EXHAUST SYSTEM EXHAUST SYSTEM DIAGNOSIS CHART CONDITION POSSIBLE CAUSE CORRECTION EXCESSIVE EXHAUST NOISE OR LEAKING EXHAUST GASES Leaks at pipe join ...

Specifications

TORQUE SPECIFICATIONS ...

Other materials:

Description and operation
Exhaust system DESCRIPTION The basic exhaust system consists of exhaust manifold( s), exhaust pipe with oxygen sensors, catalytic converter(s), heat shield(s), muffler and tailpipe (Fig. 1) (Fig. 2) (Fig. 3) Fig. 1 Exhaust Pipe-2.5L 1 - NUT 2 - TRANSMISSION SUPPORT 3 - MINI CATALYTIC CON ...