Chrysler PT Cruiser. Manual - part 723

MUFFLER

REMOVAL

WARNING: THE NORMAL OPERATING TEMPERA-
TURE OF THE EXHAUST SYSTEM IS VERY HIGH.
THEREFORE, NEVER WORK AROUND OR 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 CON-
VERTER RISES TO A HIGH LEVEL AFTER A SHORT
PERIOD OF ENGINE OPERATING TIME.

(1) Raise vehicle on hoist and apply penetrating oil

to band clamp fastener of component being removed.

NOTE: Do not use petroleum-based lubricants when
removing/installing muffler or exhaust pipe isola-
tors as it may compromise the life of the part. A
suitable substitute is a mixture of liquid dish soap
and water.

(2) Remove exhaust system ground strap at rear of

muffler.

(3) Loosen band clamp and remove support isola-

tors at muffler. Remove muffler from intermediate
pipe (Fig. 3).

(4) Clean ends of pipes and muffler to assure mat-

ing of all parts. Discard broken or worn isolators,
rusted or overused clamps, supports, and attaching
parts.

NOTE: When replacement is required on any com-
ponent of the exhaust system, you must use origi-
nal equipment parts (or their equivalent).

INSTALLATION

When assembling exhaust system do not tighten

clamps until components are aligned and clearances
are checked.

(1) Install the muffler to intermediate pipe and the

isolator supports to the underbody.

(2) Working from the front of system; align each

component to maintain position and proper clearance
with underbody parts (Fig. 2). For clearance specifi-
cations (Refer to 11 - EXHAUST SYSTEM - SPECI-
FICATIONS). Tighten band clamp to 47 N·m (35 ft.
lbs.) (Fig. 4).

Fig. 3 Muffler

1 - CLAMP
2 - INTERMEDIATE PIPE
3 - ISOLATOR
4 - CLAMP

5 - HANGER
6 - MUFFLER
7 - HANGER
8 - ISOLATOR

11 - 6

EXHAUST SYSTEM AND TURBOCHARGER

CAUTION: Band clamps should never be tightened
such that the two sides of the clamps are bottomed
out against the center hourglass shaped center
block. Once this occurs, the clamp band has been
stretched and has lost its clamping force and must
be replaced.
To replace the band clamp; remove the nut and peel
back the ends of the clamp until spot weld breaks.
File or grind remaining weld material until pipe sur-
face is smooth.

NOTE: Maintain proper clamp orientation when
replacing with new clamp.

(3) Connect the exhaust system ground strap.

(4) Start the engine and inspect for exhaust leaks.

Repair exhaust leaks as necessary.

(5) Check the exhaust system for contact with the

body panels. Make the necessary adjustments, if
needed.

INTERMEDIATE PIPE

REMOVAL

(1) Raise vehicle on hoist and apply penetrating oil

to band clamp fastener of component being removed.

(2) Remove muffler (Refer to 11 - EXHAUST SYS-

TEM/MUFFLER - REMOVAL).

(3) Loosen band clamp and remove support isola-

tor. Remove intermediate pipe from catalytic con-
verter pipe (Fig. 5).

(4) Clean ends of pipes and muffler to assure mat-

ing of all parts. Discard broken or worn isolators,
rusted or overused clamps, supports, and attaching
parts.

NOTE: When replacement is required on any com-
ponent of the exhaust system, you must use origi-
nal equipment parts (or their equivalent).

INSTALLATION

When assembling exhaust system do not tighten

clamps until components are aligned and clearances
are checked.

(1) Install intermediate pipe and the isolator sup-

ports to the underbody (Fig. 5).

(2) Install muffler (Refer to 11 - EXHAUST SYS-

TEM/MUFFLER - INSTALLATION).

(3) Working from the front of system; align each

component to maintain position and proper clearance
with underbody parts (Fig. 2). For clearance specifi-
cations (Refer to 11 - EXHAUST SYSTEM - SPECI-
FICATIONS).

(4) Tighten band clamps to 47 N·m (35 ft. lbs.)

(Fig. 6).

NOTE: Maintain proper clamp orientation when
replacing with new clamp.

(5) Start the engine and inspect for exhaust leaks.

Repair exhaust leaks as necessary.

Fig. 4 Band Clamp

1 - CLAMP SIZE
2 - TORQUE SPECIFICATION

EXHAUST SYSTEM AND TURBOCHARGER

11 - 7

MUFFLER (Continued)

(6) Check the exhaust system for contact with the

body panels. Make the necessary adjustments, if
needed.

CATALYTIC CONVERTER

DESCRIPTION

An under-floor catalytic converter inlet is attached

to the exhaust manifold using fasteners and a gasket
for sealing (Fig. 7). A flex joint that is integral to the
converter allows movement between the engine and
the exhaust system. The converter outlet attaches to
the intermediate pipe.

OPERATION

The three-way catalytic converter simultaneously

converts three exhaust emissions into harmless
gases. Specifically, HC and CO emissions are con-
verted into water (H2O) and carbon dioxide (CO2).
Oxides of Nitrogen (NOx) are converted into Nitrogen
(N) and Oxygen. The three-way catalyst is most effi-
cient in converting HC, CO and NOx at the stoichio-
metric air fuel ratio of 14.7:1.

Fig. 5 Intermediate Pipe

1 - CLAMP
2 - CATALYTIC CONVERTER PIPE
3 - INTERMEDIATE PIPE

4 - ISOLATOR
5 - HANGER

Fig. 6 Band Clamp

1 - CLAMP SIZE
2 - TORQUE SPECIFICATION

11 - 8

EXHAUST SYSTEM AND TURBOCHARGER

INTERMEDIATE PIPE (Continued)

The oxygen content in a catalyst is important for

efficient conversion of exhaust gases. When a high
oxygen content (lean) air/fuel ratio is present for an
extended period, oxygen content in a catalyst can
reach a maximum. When a rich air/fuel ratio is
present for an extended period, the oxygen content in
the catalyst can become totally depleted. When this
occurs, the catalyst fails to convert the gases. This is
known as catalyst

9punch through.9

Catalyst operation is dependent on its ability to

store and release the oxygen needed to complete the
emissions-reducing chemical reactions. As a catalyst
deteriorates, its ability to store oxygen is reduced.
Since the catalyst’s ability to store oxygen is some-
what related to proper operation, oxygen storage can
be used as an indicator of catalyst performance.
Refer to the appropriate Diagnostic Information for
diagnosis of a catalyst related Diagnostic Trouble
Code (DTC).

The combustion reaction caused by the catalyst

releases additional heat in the exhaust system, caus-
ing temperature increases in the area of the reactor
under severe operating conditions. Such conditions
can exist when the engine misfires or otherwise does
not operate at peak efficiency. Do not remove spark
plug wires from plugs or by any other means short
out cylinders. Failure of the catalytic converter can
occur

due

temperature

increases

caused

unburned fuel passing through the converter. This
deterioration of the catalyst core can result in exces-
sively high emission levels, noise complaints, and
exhaust restrictions.

Unleaded gasoline must be used to avoid ruining

the catalyst core. Do not allow engine to operate
above 1200 RPM in neutral for extended periods over
5 minutes. This condition may result in excessive

exhaust system/floor pan temperatures because of no
air movement under the vehicle.

The flex joint allows flexing as the engine moves,

preventing breakage that could occur from the back-
and-forth motion of a transverse mounted engine.

CAUTION: Due to exterior physical similarities of
some catalytic converters with pipe assemblies,
extreme care should be taken with replacement
parts.

There

are

internal

converter

differences

required in some parts of the country (particularly
vehicles

built

for

States

with

strict

emission

requirements) and between model years.

REMOVAL

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.

NOTE: Before replacing a catalytic converter, deter-
mine the root cause of failure. Most catalytic con-
verter failures are caused by air, fuel or ignition
problems. Refer to the appropriate service diagnos-
tic information for repair procedures.

(1) Loosen intermediate pipe-to catalytic converter

clamp.

(2) Remove muffler/intermediate pipe insolators as

necessary to slide muffle/intermediate pipe assembly
out of catalytic converter.

(3) 1.6L Engine - Disconnect upstream oxygen sen-

sor electrical connector.

(4) Disconnect downstream oxygen sensor electri-

cal connector (Fig. 8).

(5) Remove catalytic converter to exhaust manifold

attaching fasteners and remove converter from vehi-
cle (Fig. 9), (Fig. 10), (Fig. 11) or (Fig. 12).

(6)

Remove and discard flange gasket.

NOTE: When replacement is required on any com-
ponent of the exhaust system, original equipment
parts (or equivalent) must be used.

Fig. 7 Catalytic Converter - Typical

1 - FLEX JOINT
2 - CATALYTIC CONVERTER
3 - OXYGEN SENSOR

EXHAUST SYSTEM AND TURBOCHARGER

11 - 9

CATALYTIC CONVERTER (Continued)

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