1999 LAND ROVER DEFENDER air condition

12ENGINE
12
DESCRIPTION AND OPERATION GENERAL
The Td5 diesel engine is a 2.5 litre, 5 cylinder, in-line direct injection unit having 2 valves per cylinder, operated by
a single overhead camshaft. The engine emissions on pre EU3 models comply with ECD2 (European Commission
Directive) legislative requirements. EU3 models comply with ECD3 legislative requirements. Both units employ
electronic engine management control, positive crankcase ventilation and exhaust gas recirculation to limit the
emission of pollutants. The unit is water cooled and turbo-charged and is controlled by an electronic engine
management system.
The cylinder block is a monobloc cast iron construction with an aluminium stiffening plate fitted to the bottom of the
cylinder block to improve lower structure rigidity. The cylinder head and sump are cast aluminium. An acoustic
cover is fitted over the upper engine to reduce engine generated noise.
The engine utilises the following features:
Electronic Unit Injectors (EUI’s)controlled by an Engine Management System for precise fuel delivery under
all prevailing operating conditions.
Turbochargingwhich delivers compressed air to the combustion chambers via an intercooler for improved
power output.
Fuel Cooler
Oil Cooler
Centrifuge Oil Filter
Hydraulic Lash Adjusterswith independent finger followers
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ENGINE
1
ADJUSTMENT ENGINE OIL PRESSURE CHECK
Service repair no - 12.90.09.01
Check
1.Remove oil pressure switch.See Repair.
2.Connect pressure check kitLRT-12-052C
adaptor and gauge to oil pressure switch
position on oil cooler.
3.Check and if necessary, top-up engine oil.
4.Run engine at idle speed and check that oil
pressure is within limits given.
5.Switch off ignition.
6.Remove oil pressure check kitLRT-12-052C.
7.Clean oil spillage.
8.Fit oil pressure switch.See Repair.
Adjust
1.If engine oil pressure is not within specified
limits, check condition of oil pump and/or main
and connecting rod bearings.
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12ENGINE
30
REPAIR Refit
10.Clean oil cooler and mating faces.
11.Fit oil pressure switch and tighten to9Nm(7
lbf.ft).
12.Position oil cooler using a new gasket and
tighten bolts to25 Nm (18 lbf.ft).
13.Position oil filter adaptor, fit new gasket and
tighten bolts to25 Nm (18 lbf.ft).
14.Position oil filter element hand tight then a
further half turn.
15.Position coolant hose to oil cooler and secure
clip.
16.Position coolant pipe and tighten clutch housing
bolt to50 Nm (37 lbf.ft).
17.Connect oil pressure switch multiplug.
18.Fit centrifuge assembly.See this Section.
19.Refill cooling system.See COOLING SYSTEM,
Adjustment.
20.Top up engine oil.CENTRIFUGE ASSEMBLY
Service repair no - 12.60.90
Remove
1.Remove fixings and remove underbelly panel.
See CHASSIS AND BODY, Repair.
2.Remove 2 bolts securing centrifuge drain pipe to
engine sump and discard gasket.
3.Remove turbocharger.See FUEL SYSTEM,
Repair.
Models with air conditioning only
4.Remove auxiliary drive belt.See
ELECTRICAL, Repair.
5.Remove 4 bolts securing compressor and move
to one side.
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ENGINE
31
REPAIR All Models
6.Remove 3 bolts securing centrifuge to engine oil
cooler.
7.Remove centrifuge and discard’O’ring.
8.Remove 2 bolts, remove drain pipe from
centrifuge and discard gasket.Refit
9.Clean mating faces of centrifuge, oil cooler and
sump.
10.Position drain pipe to centrifuge using new
gasket and tighten bolts to10 Nm (7 lbf.ft).
11.Position new’O’ring to oil cooler.
12.Position centrifuge and tighten bolts to25 Nm
(18 lbf.ft).
13.Align drain pipe to sump, fit new gasket and
tighten bolts to10 Nm (7 lbf.ft)
Models with air conditioning only
14.Position compressor and tighten bolts to25 Nm
(18 lbf.ft).
15.Fit auxiliary drive belt.See ELECTRICAL,
Repair.
All Models
16.Fit turbocharger.See FUEL SYSTEM, Repair.
17.Fit underbelly panel.See CHASSIS AND
BODY, Repair.
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ENGINE
1
OVERHAUL GASKET - INLET MANIFOLD
Service repair no - 30.15.08.01
Remove
NOTE: The following procedure covers
both EU3 and non EU3 engines
NOTE: EU3 Engine in main illustration, Pre
EU3 condition shown in inset.
1.Remove and discard 2 Allen screws securing
EGR pipe or EGR cooler to exhaust manifold.
2.Remove bolt securing EGR pipe to cylinder
head, (if fitted)
3.Disconnect multiplug from IAT and MAP sensor.
4.Remove 4 bolts securing fuel cooler to inlet
manifold. and remove cooler.
5.Remove bolt securing engine dipstick tube to
camshaft carrier.
6.Release and remove engine dipstick tube.
7.Remove’O’ring from dip stick tube.
8.Disconnect 4 leads from glow plugs.
9.Remove 2 nuts and 8 bolts and remove inlet
manifold.
10.Remove manifold gasket.Refit
1.Clean inlet manifold and mating face, clean
mating faces of EGR pipe, exhaust manifold and
EGR cooler (if fitted).
2.Fit new gasket.
3.Position inlet manifold and working from the
centre outwards, fit inlet manifold nuts and bolts
and tighten to25 Nm (18 lbf.ft).
4.Connect glow plug leads.
5.Clean engine dipstick tube.
6.Fit new’O’ring to dipstick tube.
7.Fit engine dipstick tube to camshaft carrier and
tighten bolt to10 Nm (7 lbf.ft).
8.Position fuel cooler and tighten bolts to25 Nm
(18 lbf.ft).
9.Connect multiplug to IAT and MAP sensor.
10.Position EGR pipe or EGR cooler to exhaust
manifold and using new Allen screws tighten to
10 Nm (7 lbf.ft).
11.Fit EGR pipe clamp to cylinder head, (if fitted)
and tighten bolt to10 Nm (7 lbf.ft).
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EMISSION CONTROL
5
DESCRIPTION AND OPERATION
CAUTION: Inset A shows the Pre-EU3 condition for the EGR pipe. Inset B shows the Pre-EU3
condition filter and venting.
1.ILT valve modulator
2.ILT modulator vacuum hose (brown)
3.EGR valve modulator
4.EGR modulator vacuum hose (brown)
5.Vent hose - EGR modulator to in-line filter (green)
6.Vacuum hose to ILT valve suction port (blue)
7.Vacuum hose to EGR valve suction port (blue)
8.’T’-piece (4-way)
9.Vacuum hose to brake servo
10.Non-return valve
11.Brake servo
12.Inlet manifold
13.Exhaust manifold
14.ILT valve
15.EGR cooler - EU-3 models
16.Vacuum pump/alternator assembly
17.Air intake hose from intercooler
18.EGR valve (incorporating ILT valve) assembly
19.Vacuum hose to vacuum pump
20.Vent hose - ILT valve modulator to in-line filter (green)
21.3-way connector
22.Vent hose to air cleaner
23.ILT modulator harness connector (green)
24.EGR modulator harness connector (black)
25.To atmosphere - Pre-EU3 models
26.In-line filter - Pre-EU3 models
27.EGR pipe - Pre-EU3 models
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EMISSION CONTROL
7
DESCRIPTION AND OPERATION CRANKCASE EMISSION CONTROL
All internal combustion engines generate oil vapour and smoke in the crankcase as a result of high crankcase
temperatures and piston ring and valve stem blow-by. A closed crankcase ventilation system is used to vent
crankcase gases back to the air induction system and so reduce the emission of hydrocarbons.
Gases from the crankcase are drawn into the inlet manifold to be burnt in the combustion chambers with the fresh
air/fuel mixture. The system provides effective emission control under all engine operating conditions.
Crankcase gases are drawn through the breather port in the top of the camshaft cover and routed through the
breather hose and breather valve on the flexible air intake duct to be drawn into the turbocharger intake for
delivery to the air inlet manifold via the intercooler.
An oil separator plate is included in the camshaft cover which removes the heavy particles of oil before the
crankcase gas leaves via the camshaft cover port. The rocker cover features circular chambers which promote
swirl in the oil mist emanating from the cylinder head and camshaft carrier. As the mist passes through the series
of chambers between the rocker cover and oil separator plate, oil particles are thrown against the separator walls
where they condense and fall back into the cylinder head via two air inlet holes located at each end of the rocker
cover.
The breather valve is a pressure depression limiting valve which progressively closes as engine speed increases,
thereby limiting the depression in the crankcase. The valve is of moulded plastic construction and has a port on
the underside which plugs into a port in the flexible air duct. A port on the side of the breather valve connects to
the camshaft cover port by means of a breather hose which is constructed from a heavy duty braided rubber hose
which is held in place by hose clips. A corrugated plastic sleeve is used to give further protection to the breather
hose. The breather valve is orientation sensitive, and’TOP’is marked on the upper surface to ensure it is
mounted correctly.
It is important that the system is air tight. Hose connections to ports should be checked and the condition of the
breather hose should be periodically inspected to ensure it is in good condition.
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17EMISSION CONTROL
8
DESCRIPTION AND OPERATION EXHAUST GAS RECIRCULATION
The exhaust gas recirculation (EGR) valve permits a controlled amount of exhaust gas to combine with the fresh
air entering the engine. The exhaust gas reduces the combustion temperature by delaying the fuel burning rate,
which assists in reducing the quantity of oxides of nitrogen.
On EU3 models, an EGR cooler is employed to further reduce the combustion temperature. By passing the
exhaust gas through a bundle of pipes flooded by coolant, the density of the exhaust gas going into the engine is
increased. This process further reduces the amount of NO
2in the exhaust.
Recirculation of too much exhaust gas can result in higher emissions of soot, HC and CO due to insufficient air.
The recirculated exhaust gas must be limited so that there is sufficient oxygen available for combustion of the
injected fuel in the combustion chamber. To do this the ECM is used to control the precise quantity of exhaust gas
to be recirculated in accordance with the prevailing operating conditions. Influencing factors include:
The mass of air flow detected by the MAF sensor.
The ambient air temperature detected by the AAP sensor. This is used to initiate adjustments to reduce the
amount of smoke produced at high altitudes.
The mass of air flow detected by the MAF sensor.
The ambient air temperature detected by the AAP sensor. This is used to initiate adjustments to reduce the
amount of smoke produced at high altitudes.
Other factors which are taken into consideration by the engine management system for determining the optimum
operating condition include:
Manifold inlet air temperature
Coolant temperature
Engine speed
Fuel delivered
The main components of the EGR system are as follows.
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