1999 LAND ROVER DEFENDER lock

12ENGINE
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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
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DESCRIPTION AND OPERATION CYLINDER BLOCK
The cylinders and crankcase are contained in a single cast iron construction. The cylinders are direct bored and
plateau honed with lubrication oil supplied via lubrication jets for piston and gudgeon pin lubrication and cooling. It
is not possible to rebore the cylinder block if the cylinders become worn or damaged. Three metal core plugs are
fitted to the three centre cylinders on the right hand side of the cylinder block.
Lubrication oil is distributed throughout the block via the main oil gallery to critical moving parts through channels
bored in the block which divert oil to the main and big-end bearings via oil holes machined into the crankshaft. Oil
is also supplied from the cylinder block main gallery to the five lubrication jets which cool and lubricate the piston
and gudgeon pins. Plugs are used to seal both ends of the main oil gallery at front and rear of the engine block.
An oil cooler is fitted to the LH side of the engine block; ports in the oil cooler assembly mate with ports in the
cylinder block to facilitate coolant flow. Oil is diverted through the oil cooler, centrifuge filter and full-flow filter
before supplying the main oil gallery. A tapping in the oil filter housing provides a lubrication source for the
turbocharger bearings and an oil pressure switch is included in a tapping in the oil cooler housing which
determines whether sufficient oil pressure is available to provide engine lubrication and cooling.
Cylinder cooling is achieved by water circulating through chambers in the engine block casting. A threaded coolant
jacket plug is located at the front RH side of the cylinder block.
Cast brackets are bolted to both sides of the engine block for mounting the engine to the chassis on the LH and
RH hydramount studs.
The gearbox bolts directly to the engine block; a gearbox shim plate is located between the adjoining faces of the
gearbox and the flywheel side of the engine block and is fixed to the rear of the engine block by two bolts. Two
hollow metal dowels locate the rear of the cylinder block to the shim plate. The gearbox casing provides the
mounting for the starter motor.
A port is included at the rear left hand side of the cylinder block which connects to the turbocharger oil drain pipe
to return lubrication oil to the sump. A plug sealing the lubrication cross-drilling gallery is located at the front right
hand side of the cylinder block and plugs for the main lubrication gallery are located at the front and rear of the
cylinder block. Two plastic dowels are used to locate the cylinder head to the cylinder block and must be replaced
every time the cylinder head is removed from the cylinder block.
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12ENGINE
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DESCRIPTION AND OPERATION Oil cooler
1.Front oil gallery - full-flow filter to oil cooler matrix
2.Full-flow filter adaptor outlet port to oil cooler
(opens at 74°C)
3.Full-flow filter inlet port
4.Oil cooler housing
5.Full-flow filter outlet port to cylinder block
6.Coolant inlet port
7.Oil cooler banjo bolt seals (2 off)
8.Banjo bolts (2 off)
9.Banjo bolt oil holes - to oil cooler matrix
10.Rear oil gallery - full-flow filter / oil cooler outlet
to cylinder block11.Centre oil gallery - from pump to full-flow filter
12.Inlet port to centrifuge filter
13.Sealing ring - centrifuge filter housing to oil
cooler housing
14.Port - oil cooler matrix
15.Oil cooler matrix
16.Inlet port from pump via cylinder block to oil
cooler housing
17.Outlet port from oil cooler housing to cylinder
block
18.Rear view of oil cooler housing
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ENGINE
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DESCRIPTION AND OPERATION The engine oil cooler assembly is located on the left hand side of the engine block behind the oil centrifuge and oil
filter. The housing is bolted to the engine block by seven bolts. A matrix is included in the oil cooler housing which
acts as a heat exchanger. Coolant flow circulates through the oil cooler housing under pressure from the coolant
pump and distributes the flow evenly around the matrix fins and then along the block into three core holes for
cylinder cooling. Coolant enters the oil cooler through a pipe with a rubber hose extension at the rear side of the
engine. The coolant hose is attached to the stub pipe of the oil cooler by a spring clip.
Oil, drawn from the sump by the oil pump, passes through the oil cooler via the cylinder block. The flow of coolant
around the exterior surface of the oil cooler matrix cools a proportion of the engine oil flow as it passes through the
oil cooler.
The oil cooler is sealed to the cylinder block by a gasket which must be replaced every time the oil cooler housing
is removed.
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12ENGINE
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DESCRIPTION AND OPERATION Oil filters
The Td5 engine features two types of oil filter; the main filter is a standard disposable cartridge-type full flow oil
filter which is augmented with a by-pass centrifuge filter used to filter out particulate matter having a smaller
diameter smaller than 15 micron but greater than 3 micron.
1.Centre spindle
2.Spindle oil holes (2 off)
3.Centrifuge filter housing
4.Centrifuge filter drain pipe
5.Port - centrifuge filter drain pipe to sump6.Filter rotor
7.Internal seal
8.Cover
9.Cover screws (2 off)
The centrifuge filter is located on the left hand side of the engine block by the exhaust manifold and is housed in a
pot which is bolted to the oil cooler housing by means of three bolts. The pot contains a rotor located on a central
spindle which spins at up to 15,000 rev/min when oil is flowing through the unit under pressure. The rotor contains
two fine holes drilled at obtuse angles which cause the rotor to spin about the centre spindle when high pressure
oil is passing through it. The inner surface of the rotor captures carbon deposits and small particulate matter as it
is thrown outwards under centrifugal force to form a sludge on the inner walls of the rotor. The unit is able to trap
very fine impurities that build up in the oil that would be too small to filter using the normal paper-element type
full-flow filters alone.
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12ENGINE
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DESCRIPTION AND OPERATION Oil filter housing thermostat
1.Circlip
2.Thermostat end cap
3.Oil seal
4.Thermostatic valve5.Return spring
6.Oil filter housing
7.Threaded insert
The oil filter housing contains a thermostatically controlled valve to control the direction and proportion of oil flow
through the oil cooler matrix. When the oil temperature is cool, the centre spindle of the thermostatic element is
compressed. In this condition the valve completely seals the passage to the turbocharger feed tapping and flow is
directed through the oil filter adaptor housing, passing from the outlet of the full-flow filter to the cylinder block via
the rear oil return gallery in the oil cooler housing. A proportion of the oil flow from the right hand filter outlet port is
passed through to the oil cooler matrix to supply the turbocharger oil feed line.
When the oil temperature rises, the heated wax in the thermostat causes the thermostat centre spindle to rise and
push against the housing end cap, compressing the valve spring further and so opening the valve. In this
condition, oil flow from the outlet side of the full-flow filter is allowed to pass directly to the turbocharger oil feed
line and reverses the flow through the oil cooler matrix, which now delivers a proportion of cooled oil flow to the
cylinder block via the outlet port at the right hand side of the oil cooler housing.
The filter canister contains a by-pass valve which opens when the engine is cold or if the filter becomes blocked.
The by-pass valve opens when a pressure drop of greater than 1.6 kg/cm
2(157 kPa, 23 lbf/in2) is experienced.
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12ENGINE
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DESCRIPTION AND OPERATION CRANKSHAFT, SUMP AND OIL PUMP
The crankshaft, sump and oil pump components are described below:
Sump
The sump is a wet-type, of aluminium construction and is sealed to the engine block by means of a rubber gasket
and twenty fixing bolts. The four bolts at the gearbox end of the sump are longer than the other sixteen bolts.
The sump gasket incorporates compression limiters (integrated metal sleeves) at the bolt holes, which are
included to prevent distortion of the gasket when the sump to cylinder block bolts are being tightened.
An oil drain plug is fitted at the bottom of the oil sump reservoir. An oil return drain pipe is also attached to the oil
sump which returns oil from the centrifugal filter.
Stiffener Plate
The stiffener plate assembly provides lower engine block rigidity and utilises dowels to align it to the bottom of the
cylinder block. A rotary oil pump is integral with the stiffener plate and an oil pick-up and strainer assembly is fitted
to the underside of the stiffener plate. The stiffener and oil pump assembly is secured to the cylinder block by 22
bolts.
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ENGINE
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DESCRIPTION AND OPERATION Oil pump
1.Stiffener plate
2.Ring dowel
3.Outlet port
4.Outer rotor
5.Inner rotor6.Spring dowel
7.Oil pressure relief valve cap
8.Oil pressure relief valve spring
9.Oil pressure relief valve plunger
10.Inlet port
The eccentric rotor oil pump is integrated with the stiffener plate and contains no serviceable parts except for the
pressure relief valve spring. The oil pump drive sprocket is attached to the front of the stiffener plate and is driven
through a chain and sprocket system.
A pressure relief valve is included at the outlet side of the oil pump to restrict oil pressure at high engine speeds by
recirculating oil through the relief valve back around the pump to the inlet. The relief valve and spring is a plunger
type. When oil pressure is great enough to lift the plunger, oil is allowed to escape past the plunger to relieve
pressure and prevent further rise.
Oil is delivered to the pump from the pick-up through a channel in the stiffener plate. The outlet side of the oil
pump delivers pressurised oil flow to the engine block main oil delivery gallery through a port in the stiffener plate.
Piston lubrication jets
Piston lubrication jets are fitted to the cylinder block to provide lubrication to the cylinder walls and to the piston
underskirt for cooling the pistons and lubricating the gudgeon pins. The input port to each lubrication jet mates
with a port provided in each mounting position tapped at the underside of the cylinder block from the main oil
delivery gallery. When oil pressure is sufficient to supply flow through the jets, oil is squirted to the inside of the
cylinder walls to provide piston to wall lubrication and cooling and to the underside of the piston skirt at the bottom
of the piston stroke (gallery cooled piston). The squirt jets also provide splash feed lubrication supply to the small
end bearings of the connecting rods.
Each lubrication jet is fixed to a mounting position on the underside of the engine block by a single Torx screw.
Chain lubrication jet
A chain lubrication jet is located on the front face of the cylinder block, behind the front engine timing chain cover.
The inlet port to the lubrication jet mates with an oil supply port from the cylinder block main oil delivery gallery.
The lubrication jet is fixed to the front of the engine block by a single screw. Additional chain lubrication is provided
by oil supply through a small aperture tapped from the cylinder head oil delivery gallery.
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