Jeep Wrangler TJ. Manual - part 456

REMOVAL - 4.0L

WARNING: THE NORMAL OPERATING TEMPERA-
TURE 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 CON-
VERTER. THE TEMPERATURE OF THE CONVERTER
RISES TO A HIGH LEVEL AFTER A SHORT PERIOD
OF ENGINE OPERATION TIME.

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

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

(1) Raise and support the vehicle.
(2) Saturate the studs and nuts with a Mopar

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 (Fig. 6).

(5) Remove catalytic converter to muffler flange

retaining nuts (Fig. 6).

(6) Slide exhaust pipe foward until exhaust pipe

hanger

disengages

from

transmission

support.

Remove exhaust pipe and catalytic converter from
vehicle.

INSTALLATION

INSTALLATION - 2.4L

(1) Position exhaust pipe and catalytic converter

into vehicle.

(2) Insert exhaust pipe hanger into transmission

support (Fig. 5).

(3) Install exhaust pipe onto exhaust manifold DO

NOT tighten bolts at this time.

(4) Position muffler flange onto catalytic converter

flange and install retaining bolts and nuts (Fig. 5).
DO NOT tighten nuts at this time.

(5) Make sure the exhaust system is aligned and

has the proper clearance. The minimum clearance is
25mm (1 inch).

(6) Tighten muffler to catalytic converter flange

retaining nuts to 28.5 N·m (21 ft. lbs.).

(7) Tighten exhaust pipe to exhaust manifold

mounting bolts to 31 N·m (23 ft. lbs.).

(8) Install the oxygen sensors in the exhaust pipe

and catalytic converter.

(9) Lower vehicle.
(10) Start engine and inspect for leaks. Repair

exhaust leaks as necessary.

(11) Check the exhaust system for contact with the

body panels. Make the necessary adjustments, if
needed.

Fig. 5 Exhaust Pipe and Calalytic Converter - 2.4L

1 - CATALYTIC CONVERTER
2 - TRANSMISSION SUPPORT
3 - EXHAUST HANGER
4 - EXHAUST PIPE

Fig. 6 Exhaust Pipe and Catalytic Converter - 4.0L

1 - CATALYTIC CONVERTER
2 - TRANSMISSION SUPPORT
3 - EXHAUST HANGER
4 - EXHAUST PIPE

EXHAUST SYSTEM

11 - 7

EXHAUST PIPE (Continued)

INSTALLATION - 4.0L

(1) Position exhaust pipe and catalytic converter

into vehicle.

(2) Insert exhaust pipe hanger into transmission

support (Fig. 6).

(3) Install exhaust pipe onto exhaust manifold DO

NOT tighten bolts at this time.

(4) Position muffler flange onto catalytic converter

flange and install retaining bolts and nuts (Fig. 6).
DO NOT tighten nuts at this time.

(5) Make sure the exhaust system is aligned and

has the proper clearance. The minimum clearance is
25mm (1 inch).

(6) Tighten muffler to catalytic converter flange

retaining nuts to 28.5 N·m (21 ft. lbs.).

(7) Tighten exhaust pipe to exhaust manifold

mounting bolts to 31 N·m (23 ft. lbs.).

(8) Install the oxygen sensors in the exhaust pipe

and catalytic converter.

(9) Lower vehicle.
(10) Start engine and inspect for leaks. Repair

exhaust leaks as necessary.

(11) Check the exhaust system for contact with the

body panels. Make the necessary adjustments, if
needed.

HEAT SHIELDS

DESCRIPTION

Heat shields (Fig. 7) are made of stamped/formed

steel, or metal foil.

Exhaust heat shields are needed to protect both the

vehicle and the environment from the high tempera-
tures developed by the catalytic converter. The cata-
lytic converter releases additional heat into the
exhaust system. Under severe operating conditions,
the temperature increases in the area of the converter.
Such conditions can exist when the engine misfires or
otherwise does not operate at peak efficiency.

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. 8)
and (Fig. 9).

(3) When removing muffler heat shield, the muf-

fler 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 (Fig. 8)
and (Fig. 9).

(2) Tighten the nuts and/or screws to 45 N·m (33

ft. lbs.).

(3) Lower the vehicle.

Fig. 7 Exhaust Heat Shield - Typical

1 - HEAT SHIELD

Fig. 8 Muffler Heat Shield - Rear

1 - MUFFLER HEAT SHIELD - REAR
2 - NUTS
3 - SELF TAPPING SCREWS

Fig. 9 Muffler Heat Shield - Middle

1 - MUFFLER HEAT SHIELD - MIDDLE
2 - NUTS
3 - SELF TAPPING SCREWS

11 - 8

EXHAUST SYSTEM

EXHAUST PIPE (Continued)

MUFFLER

DESCRIPTION

Both the 2.4L and 4.0L engines use a galvanized

steel muffler (Fig. 10) to control exhaust noise levels
and exhaust back pressure.

REMOVAL

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

All original equipment exhaust systems are manu-

factured with the exhaust tailpipe welded to the muf-
fler.

Service

replacement

mufflers

and

exhaust

tailpipes are either clamped together or welded
together.

(1) Raise the vehicle and support the rear of the

vehicle by the side rails and allow the axle to hang
free.

(2) Remove the tailpipe hangers from the insula-

tors (Fig. 11).

(3) Remove muffler to catalytic converter flange

retaining nuts (Fig. 11).

(4) Remove muffler and tailpipe assembly from

vehicle.

Fig. 10 Muffler

1 - MUFFLER

EXHAUST SYSTEM

11 - 9

INSTALLATION

(1) Position muffler and tailpipe assembly into

vehicle.

(2) Position muffler and catalytic converter flanges

together and install nuts (Fig. 11). DO NOT tighten
nuts at this time.

(3) Install tailpipe hangers into the insulators (Fig.

11).

(4) Make sure the muffler and tailpipe are cor-

rectly positioned and the proper alignment. The min-
imum clearance between components is 25mm (1
inch).

(5) Tighten muffler to catalytic converter flange

nuts to 28.5 N·m (21 ft. lbs.).

(6) Lower vehicle.

(7) Start engine and inspect for leaks. Repair

exhaust leaks as necessary.

(8) Check the exhaust system for contact with the

body panels. Make the necessary adjustments, if
needed.

Fig. 11 Muffler and Tailpipe

1 - TRANSMISSION SUPPORT
2 - TAILPIPE HANGER INSULATORS
3 - TAILPIPE HANGERS
4 - TAILPIPE

5 - MUFFLER
6 - MUFFLER TO CATALYTIC CONVERTER FLANGE
7 - NUTS
8 - CATALYTIC CONVERTER

11 - 10

EXHAUST SYSTEM

MUFFLER (Continued)

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