Frelander 2. Manual — part 379
Exhaust System - I6 3.2L Petrol - Exhaust System
Description and Operation
COMPONENT LOCATION
Item
Part Number
Description
1
-
Heated Oxygen Sensor (HO2S) - Pre-Catalyst (2 off)
2
-
Gasket (2 off)
3
-
HO2S - Post catalyst (2 off)
4
-
Flexible coupling
5
-
Gasket
6
-
Tailpipe finisher (optional)
7
-
Mounting rubber (6 off)
8
-
Rear muffler
9
-
Centre muffler
10
-
Flange
11
-
Bracket
12
-
Catalytic converter (2 off)
13
-
Flange
14
-
Catalytic converter (2 off)
15
-
Exhaust manifold gaskets
OVERVIEW
The 3.2L SI6 exhaust system is fabricated from stainless steel and is supplied as two separate assemblies; a front section
incorporating two catalytic converters and a rear section incorporating centre and rear silencers.
EXHAUST MANIFOLDS
The exhaust manifold comprises two separate manifold assemblies. One manifold is used for cylinders 1 to 3 and the
second manifold is used for cylinders 4 to 6. The manifolds are sealed to the cylinder head with a gasket and secured with
14 bolts.
Each manifold comprises three fabricated branches which merge into an integral catalytic converter. A threaded boss is
positioned where the three branches merge and provides for the fitment of a pre-catalyst HO2S. The catalytic converter
outlets have offset flanges which mate with corresponding flanges on the front section exhaust system.
A bracket on each outlet flange allows for the attachment of an exhaust manifold heat shield.
FRONT SECTION
The front section has two flanged pipes which mate with the offset flanges of the exhaust manifolds. The flanges are
sealed with gaskets and secured with bolts. The flanges are connected via curved pipes to decouplers which provide a
flexible joint in the system. The outlet from each decoupler comprises a curved pipe with a threaded boss which provides
for the fitment of a post-catalyst HO2S.
Each pipe is connected into a smaller catalytic converter which in turn is connected to a double flange which mates with
the rear section of the exhaust system.
Two mounting rubbers are located at the rear of the flexible coupling and are attached to a bracket mounted on the front
subframe.
REAR SECTION
The rear section has a double flange which mates with the double flange of the front section. The double flanges of each
section are sealed with a gasket and secured with studs, washers and nuts. Two short pipes from the double flange
connect into the centre muffler.
The centre muffler is a fabricated unit with a capacity of 7.6 liters. The muffler comprises a pair of perforated baffle tubes
contained within the muffler body. The two baffle tubes merge into one single tube which provides the outlet from the
muffler. A rubber mounting is attached to the rear of the muffler and attaches to a hanger bracket located on the
underside of the vehicle floorpan.
A single pipe from the rear of the centre muffler is routed along the underside of the vehicle body to the rear muffler. The
pipe enters the rear muffler through a connection in the forward face of the muffler.
The rear muffler is a fabricated unit with a capacity of 29.3 liters. The rear muffler is positioned transversely at the rear of
the vehicle, forward of the rear bumper. The muffler comprises baffle plates and perforated baffle tubes. Each end of the
muffler body has an outlet which direct exhaust gasses to exit at the rear of the vehicle. The muffler is supported by a
single rubber mounting on the Left Hand (LH) side and by two rubber mountings on the Right Hand (RH) side.
CATALYTIC CONVERTERS
The catalytic converters are fitted in the front section of the exhaust system, after the HO2S.
The HO2S monitors the exhaust gasses leaving the engine. The engine management system uses this information to
provide accurately metered quantities of fuel to the combustion chambers to ensure the most efficient use of fuel and to
minimise the exhaust emissions.
In the catalytic converters, the exhaust gases are passed through honeycombed ceramic elements coated with a special
surface treatment called 'washcoat'. The washcoat increases the surface area of the ceramic elements by a factor of
approximately 7000. On top of the washcoat is a coating containing platinum, which is the active constituent for
converting harmful emissions into inert by-products. The platinum adds oxygen to the carbon monoxide and the
hydrocarbons in the exhaust gases, to convert them into carbon dioxide and water respectively.
Exhaust System - I6 3.2L Petrol - Exhaust System
Diagnosis and Testing
Principles of Operation
For a detailed description of the exhaust system, refer to the relevant Description and Operation section in the workshop
manual. REFER to:
Exhaust System
(309-00A Exhaust System - I6 3.2L Petrol, Description and Operation),
Exhaust System
(309-00B Exhaust System - TD4 2.2L Diesel, Description and Operation).
Inspection and Verification
CAUTION: Diagnosis by substitution from a donor vehicle is NOT acceptable. Substitution of control modules does
not guarantee confirmation of a fault, and may also cause additional faults in the vehicle being tested and/or the donor
vehicle.
1. Verify the customer concern.
1.
2. Visually inspect for system integrity and obvious signs of mechanical damage.
2.
Visual Inspection
Mechanical
Leaks
Metal fatigue
Pipes, mufflers and catalytic converters
Joints
Mountings
Clearance around components
3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before
proceeding to the next step.
3.
4. If the cause is not visually evident, verify the symptom and refer to the Symptom Chart.
4.
Symptom Chart
Symptom
Possible Cause
Action
Excessively
noisy/leaking exhaust
Exhaust
system/components
Inspect exhaust system, refer to Visual Inspection above
Rectify leaks or Install new components as necessary. Refer
to Removal and Installation instructions in this section
Loss of power
Restricted exhaust
system
Fuel system
Ignition system
Electronic engine
control
Install new exhaust components as necessary. Refer to
Removal and Installation instructions in this section
For fuel system tests.
REFER to:
Fuel Tank and Lines
(310-01A Fuel Tank and Lines -
I6 3.2L Petrol, Diagnosis and Testing).
For ignition system tests.
REFER to:
Engine Ignition
(303-07A Engine Ignition, Diagnosis
and Testing).
For electronic engine control tests.
REFER to:
Electronic Engine Controls
(303-14A Electronic
Engine Controls - I6 3.2L Petrol, Diagnosis and Testing) /
Electronic Engine Controls - 2.2L Duratorq-TDCi (DW) Diesel
(303-14 Electronic Engine Controls - 3.2L, Diagnosis and
Testing).
Exhaust System - I6 3.2L Petrol - Rear Muffler
Removal and Installation
Special Tool(s)
100-051
Cutter, Exhaust Pipe
Removal
• NOTE: Removal steps in this procedure may contain installation details.
1.
WARNING: Make sure to support the vehicle with axle
stands.
Raise the vehicle on a lift.
1.
Using the special tool, cut the exhaust pipe at a
distance of 300mm from the front of the rear muffler.
Special Tool(s):
100-051
2.
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