LAND ROVER DEFENDER 1999 Workshop Manual

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MANIFOLD AND EXHAUST SYSTEM
1
DESCRIPTION AND OPERATION MANIFOLD COMPONENT LAYOUT
1.Inlet manifold
2.Flanged nut - 2 off
3.Stud - 2 off
4.Stud - 10 off
5.Exhaust gasket6.Flanged nut - 10 off
7.Exhaust manifold
8.Inlet gasket
9.Flanged bolt - 8 off
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30MANIFOLD AND EXHAUST SYSTEM
2
DESCRIPTION AND OPERATION DESCRIPTION
General
The diesel engine has the inlet manifold attached to the right hand side of the engine and the exhaust manifold
attached to the left hand side of the engine. The inlet manifold directs cooled compressed air from the
turbocharger and intercooler into the cylinders, where it is mixed with fuel from the injectors. Exhaust gases from
the exhaust manifold can also be directed into the inlet manifold via a pipe from the exhaust manifold and an
Exhaust Gas Recirculation (EGR) valve on the inlet manifold. The exhaust manifold allows combustion gases from
the cylinders to leave the engine where they are directed into the exhaust system and turbocharger.
The exhaust system is attached to the turbocharger and is directed along the underside of the vehicle to emit
exhaust gases from a tail pipe at the rear of the vehicle. A silencer is installed midway along the system and a
second tail silencer is located at the rear of the vehicle.
Inlet manifold
The inlet manifold is a one piece aluminium casting. The manifold is secured to the cylinder head with two studs
and flanged nuts and eight flanged bolts. A one piece laminated gasket seals the manifold to the cylinder head.
Four threaded bosses on the manifold provide for the attachment of the fuel cooler. The fuel cooler is secured to
the manifold with four bolts. A boss with two threaded holes allows for the attachment of the combined intake air
temperature/pressure sensor. The sensor is secured to the manifold with two screws and sealed with a gasket.
At the forward end of the manifold, a machined face and four threaded holes provide for the attachment of the
EGR valve. The valve is sealed to the manifold with a gasket.
Exhaust manifold
The exhaust manifold is made from cast iron. The manifold has five ports, one from each cylinder, which merge
into one flanged outlet connection positioned centrally on the manifold.
The manifold is attached to the cylinder head with ten studs and flanged nuts. A laminated metal gasket seals the
manifold to the cylinder head. The flanged outlet on the manifold provides the attachment for the turbocharger,
which is attached with three studs and flanged nuts and sealed with a metal laminated gasket.
A second flanged outlet, located at the forward end of the manifold, provides attachment for the EGR pipe. The
EGR pipe is secured to the manifold with two cap screws and connected to the EGR valve mounted on the inlet
manifold. There is no gasket used between the pipe and the exhaust manifold.
Exhaust system
The exhaust system comprises a front pipe, an intermediate pipe which incorporates a silencer and a tail pipe
assembly which also has a silencer. The exhaust system is constructed mainly of 63 mm (2.48 in) diameter
extruded pipe with a 1.5 mm (0.06 in) wall thickness. All pipes are aluminized to resist corrosion and the silencers
are fabricated from stainless steel sheet.
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MANIFOLD AND EXHAUST SYSTEM
3
DESCRIPTION AND OPERATION Front pipe assembly
The front pipe is of welded and fabricated tubular construction. The front pipe is connected to a flange on the
turbocharger and secured with three flanged nuts and sealed with a metal laminated gasket. The front pipe
incorporates a flexible pipe near the connection with the turbocharger and terminates in a flanged connection with
the intermediate pipe.
The flexible pipe is formed into a concertina shape with woven metal strands around its outer diameter. The
flexible pipe allows for ease of exhaust system alignment and also absorbs engine vibration. The woven metal
strands also increase the longevity of the flexible pipe.
The front pipe is attached via a bracket and a mounting rubber to the chassis. The mounting rubber allows ease of
alignment and vibration absorption.
Intermediate pipe and silencer
The intermediate pipe is of welded and fabricated tubular construction. It connects at its forward end to the front
pipe flange. Two captive studs on the intermediate pipe flange allow for attachment to the front pipe with locknuts.
The rear section of intermediate pipe connects to the tail pipe assembly via a flanged joint, sealed with a metal
gasket and secured with locknuts and studs.
The forward and rear sections are joined by a silencer. The silencer is fabricated from stainless steel sheet to form
the body of the silencer. An end plate closes each end of the silencer and is attached to the body with seam joints.
Perforated baffle tubes, inside the silencer, are connected to the inlet and outlet pipes on each end plate. Internal
baffle plates support the baffle tubes and, together with a stainless steel fibre packing, absorb combustion noise
as the exhaust gases pass through the silencer.
The intermediate pipe is attached by two brackets, positioned at each end of the silencer, and two mounting
rubbers to the chassis. The mounting rubber allows for ease of alignment and vibration absorption.
Tail pipe assembly
The tail pipe is of welded and fabricated construction. The tail pipe connects to the intermediate pipe with a
flanged joint secured with locknuts and sealed with a metal gasket. The pipe is shaped to locate above the rear
axle allowing clearance for axle articulation. The pipe is also curved to clear the left hand side of the fuel tank
which has a reflective shield to protect the tank from heat generated from the pipe.
A fabricated silencer is located at the rear of the tail pipe. The silencer is circular in section and is constructed from
stainless steel sheet. A baffle tube is located inside the silencer and the space around the baffle tube is packed
with a stainless steel fibre. The holes in the baffle tube allow the packing to further reduce combustion noise from
the engine. The tail pipe from the silencer is curved downwards at the rear of the vehicle and directs exhaust
gases towards the ground. The curved pipe allows the exhaust gases to be dissipated by the airflow under the
vehicle and prevents the gases from being drawn behind the vehicle.
The tail pipe is attached by a bracket, positioned forward of the silencer, and a mounting rubber to the chassis.
The mounting rubber allows ease of alignment and vibration absorption.
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MANIFOLD AND EXHAUST SYSTEM
1
REPAIR PIPE - EXHAUST - FRONT
Service repair no - 30.10.09
Remove
1.Remove engine acoustic cover.See ENGINE ,
Repair.
2.Release clip and disconnect breather hose from
camshaft cover.
3.Release clips and disconnect air flow meter from
air filter.
4.Disconnect multiplug from air flow meter.
5.Loosen clip screw and remove air inlet hose
from turbocharger.
6.Remove 3 bolts and remove exhaust manifold
heat shield.
7.Remove 3 nuts, release front pipe from
turbocharger and discard gasket.
8.Remove underbelly panel.See CHASSIS AND
BODY, Repair.
9.Remove 8 nuts and bolts and remove chassis
cross member.
10.Remove 2 nuts, release front pipe from
intermediate silencer.
11.Release front pipe from mounting rubber and
remove pipe.
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30MANIFOLD AND EXHAUST SYSTEM
2
REPAIR Refit
12.Clean front pipe and mating faces.
13.Position front pipe and using new gaskets, align
to intermediate pipe and turbocharger.
14.Connect mounting rubber to front pipe.
15.Fit and tighten exhaust flange nuts to27 Nm (20
lbf.ft).
16.Fit chassis cross member, and tighten bolts to
45 Nm (33 lbf.ft)
17.Fit underbelly panel.See CHASSIS AND
BODY, Repair.
18.Position new gasket and front pipe to
turbocharger and tighten nuts to27 Nm (20
lbf.ft).
19.Position exhaust manifold heat shield and
tighten M6 bolts to10 Nm (7 lbf.ft)and M8 bolt
to25 Nm(18 lbf.ft).
20.Position air inlet hose to turbocharger and
tighten clip screw.
21.Connect air flow meter to air filter and secure
clips.
22.Connect air flow meter multiplug.
23.Connect breather hose and secure clip.
24.Fit engine acoustic cover.See ENGINE ,
Repair.SILENCER - INTERMEDIATE
Service repair no - 30.10.11
Remove
1.Raise vehicle on a 4 post ramp.
2.Remove 2 nuts securing intermediate silencer to
front pipe.
3.Remove 3 nuts securing intermediate silencer to
tail pipe.
4.Release intermediate silencer from rubber
mountings and remove silencer.
5.Remove and discard gasket from tail pipe flange.
Refit
6.Clean intermediate silencer and mating faces.
7.Fit new gasket to tail pipe flange.
8.Position intermediate silencer to rubber
mountings and tail pipe flange.
9.Fit nuts securing intermediate silencer to front
pipe and tail pipe and tighten to25 Nm (18
lbf.ft).
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MANIFOLD AND EXHAUST SYSTEM
3
REPAIR EXHAUST - TAIL PIPE AND SILENCER
Service repair no - 30.10.22
Remove
1.Raise vehicle on ramp.
2.Remove 3 nuts securing silencer to tail pipe.
3.Release tail pipe from mounting and remove tail
pipe.
4.Collect silencer to tail pipe gasket.
Refit
5.Clean silencer and tail pipe mating faces.
6.Position tail pipe and secure on mounting
rubber.
7.Using a new gasket, align silencer to tail pipe.
8.Fit nuts to silencer and tighten to25 Nm (18
lbf.ft).GASKET - INLET MANIFOLD
Service repair no - 30.15.08
Remove
1.Remove battery cover.
2.Disconnect battery negative lead.
3.Remove 3 bolts and remove engine acoustic
cover.
4.Release retainers and remove cooling fan cowl.
5.Disconnect multiplug from manifold air pressure
sensor and release 4 glow plug leads.
6.Remove 4 bolts, release EGR valve from inlet
manifold and discard gasket.
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30MANIFOLD AND EXHAUST SYSTEM
4
REPAIR
7.Remove 4 bolts securing fuel cooler to inlet
manifold.
8.Remove 2 bolts and remove alternator support
bracket and disconnect fuel injector harness
multiplug.
9.Remove bolt securing engine dip stick tube to
camshaft carrier.
10.Remove dip stick tube and discard’O’ring.
11.Remove 2 nuts and 8 bolts securing inlet
manifold to cylinder head.
12.Disconnect multiplugs from turbocharger boost
control soleniod, ECT sensor, ambient air
pressure sensor, MAF sensor, and A/C
compressor.
NOTE: EU3 Model illustrated.
13.Remove 2 bolts securing harness to camshaft
carrier.
14.Release harness from engine and inlet manifold.
15.Remove inlet manifold and gasket.
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MANIFOLD AND EXHAUST SYSTEM
5
REPAIR Refit
16.Clean inlet manifold and mating face.
17.Fit new gasket.
18.Fit inlet manifold, and working from the centre
outwards, tighten nuts and bolts to25 Nm (18
lbf.ft).
19.Position harness to sensors and connect
multiplugs.
20.Tighten harness clip bolts to camshaft carrier to
10 Nm (7 lbf.ft).
21.Clean dip stick tube and fit new’O’ring.
22.Fit dip stick tube and tighten bolt to10 Nm (7
lbf.ft).
23.Connect glow plug leads.
24.Fit alternator support bracket and tighten bolts to
45 Nm (33 lbf.ft).
25.Position fuel cooler. Apply Loctite 242 to bolts
and tighten to18 Nm (13 lbf.ft).
26.Fit new gasket, position EGR valve and tighten
bolts to9 Nm (7 lbf.ft).
27.Connect multiplug to MAP sensor.
28.Fit cooling fan cowl.
29.Fit engine acoustic cover.
30.Reconnect battery negative lead.
31.Fit battery cover.GASKET - EXHAUST MANIFOLD
Service repair no - 30.15.12
Remove
1.Remove turbocharger.See FUEL SYSTEM,
Repair.
2. Models with A/C:Remove auxiliary drive belt.
See ELECTRICAL, Repair.
3.Remove 4 bolts securing compressor and move
to one side.
All Models
NOTE: EU3 Model illustrated.
4.Remove and discard 2 Allen screws securing
EGR pipe to exhaust manifold.
5.Remove 10 nuts securing exhaust manifold to
cylinder head.
6.Remove exhaust manifold and gasket.
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