LAND ROVER DEFENDER 1999 Workshop Manual

12ENGINE
16
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
ProCarManuals.com

ENGINE
17
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.
ProCarManuals.com

12ENGINE
18
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.
ProCarManuals.com

ENGINE
19
DESCRIPTION AND OPERATION Full flow filter
Approximately 10% of the total oil flow enters the centrifuge pot through a side port in the pot casting which is
mated to an outlet port at the lower side of the oil cooler housing. A rubber’O’ring sits in a recess around the oil
cooler port which seals the faces between the centrifuge pot and oil cooler port, and it must be replaced every
time the centrifuge assembly is removed. Oil leaves the centrifuge pot through a drain tube which is attached to
the base of the pot by means of two fixing screws. The lower end of the drain tube returns oil to the sump and is
fixed to the sump by means of two screws. Gaskets are included at the port interfaces between the oil drain tube
and the centrifuge pot and the oil drain tube and sump return port; these gaskets must be replaced every time the
oil drain tube is removed.
The centrifuge cover is fixed to the pot by two screws and is sealed by an’O’ring.
1.Full-flow filter housing
2.Thermostat
3.Roll-pin4.Port - feed line to turbocharger
5.Outlet port from full-flow filter - higher than 74°C
6.Inlet port to full-flow filter
7.Outlet port from full-flow filter - lower than 74°C
The main filter is a conventional full flow cartridge type filter containing a paper element able to trap particles
greater than 15 micron (0.015 mm) in diameter.
The cartridge is screwed to an adaptor casting by way of a hollow brass threaded insert which connects the filter
outlet port to the adaptor casting. A sealing ring seals the union between the oil filter cartridge and the adaptor
casting.
ProCarManuals.com

12ENGINE
20
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.
ProCarManuals.com

ENGINE
21
DESCRIPTION AND OPERATION Oil pressure switch
The oil pressure switch is located in a port on the outlet side of the oil cooler housing. It detects when a safe
operating pressure has been reached during engine starting and initiates the illumination of a warning light in the
instrument pack if the pressure drops below a given value.
ProCarManuals.com

12ENGINE
22
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.
ProCarManuals.com

ENGINE
23
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.
ProCarManuals.com

12ENGINE
24
DESCRIPTION AND OPERATION Crankshaft
1.Front end to crankshaft sprocket
2.Oil supply cross-drillings
3.Main journals4.Big-end journals
5.Rear end to flywheel
The crankshaft is constructed from cast iron and is surface-hardened. The areas between the crankshaft journals
and the adjoining webs and balance weights are compressed using the cold roll process to form journal fillets.
Cross-drillings in the crankshaft between adjoining main and big-end bearings are used to divert lubrication oil to
the big-end bearings.
A torsional vibration damper is attached to the crankshaft pulley by three bolts.
The crankshaft is carried in six main bearings, with end-float being controlled by thrust washers positioned on both
sides of No. 3 main bearing.
Main bearings
There are six main bearings used to carry the crankshaft. Each of the bearing caps are of cast iron construction
and are attached to the cylinder block by two bolts.
The bearing shells are of the split cylindrical type. The upper half bearing shells are grooved to facilitate the supply
of lubrication oil to the bearings and fit into a recess in the underside of the cylinder block. The lower half bearing
shells are smooth and fit into the bearing caps.
Steel-backed, thrust washers are included at each side of No. 3 main bearing to control crankshaft end-float. One
side of each of the thrust washers is grooved, the grooved side of each of the thrust washers is fitted facing
outward from No. 3 main bearing.
ProCarManuals.com

ENGINE
25
DESCRIPTION AND OPERATION CYLINDER HEAD COMPONENTS
The cylinder head components are described below:
Cylinder head
The cylinder head is of aluminium construction. It is not possible to reface the cylinder head if it becomes worn or
damaged. An alloy camshaft carrier is bolted directly to the upper surface of the cylinder head. Two dowels are
included in the cylinder head upper face for correct location of the camshaft carrier.
The EU3 cylinder head has a single internal fuel rail for delivering fuel to the injectors and an external fuel pipe for
returning spill fuel back to the fuel connector block. Therefore, pre EU3 and EU3 cylinder heads are not
interchangeable.
CAUTION: The cylinder head incorporates drillings for the fuel injection system, any
contamination which enters these drillings could cause engine running problems or injector
failure. It is therefore, essential that absolute cleanliness is maintained when carrying out work on
the cylinder head.
The camshaft carrier and cylinder head assembly is attached to the cylinder block by twelve cylinder head
retaining bolts which pass through the camshaft carrier and the cylinder head to secure the assembly to the
cylinder block.
CAUTION: The valve heads, tips of the injectors and glow plugs protrude below the face of the
cylinder head and will be damaged if the cylinder head is stored face down.
The camshaft is located between the cylinder head and the camshaft carrier, and the bearing journals are line
bored between the two components to form a matched pair.
CAUTION: Always fit plugs to open connections to prevent contamination.
The valve guides and valve seat inserts are sintered components which are an interference fit to the cylinder
head. The cylinder head machining also provide the locations for the electronic unit injectors, glow plugs, hydraulic
lash adjusters, finger followers and low pressure fuel rail.
Cooling to the cylinder head is provided by coolant flow through a water jacket machined into the cylinder head.
Drillings through the block provide lubrication channels for pressurised oil supply to cylinder head components
such as the lash adjusters, finger followers, rocker arms and camshaft bearings.
A coolant outlet elbow is fitted to the front LH side of the cylinder head to allow flow of coolant from the cylinder
head back to the radiator. A metal gasket is used to seal the joint between the water outlet elbow and the cylinder
head. A coolant temperature sensor is located in a port in the side of the water outlet elbow for monitoring coolant
temperature.
A stub pipe is connected at the front RH side of the cylinder block above the timing cover which connects a pipe to
supply oil to the vacuum pump. The timing chain tensioner adjuster is screwed in a thread in the cylinder head at a
location on the front RH side of the engine below the oil feed port for the vacuum pump.
An access hole for the camshaft gear is included at the front of the cylinder head which is sealed with a plastic
plug and rubber’O’ring. A press-fit core plug for the chain chest is located on the front face of the cylinder head.
A press-fit core plug for the cylinder head water jacket is located at the rear of the cylinder head and a threaded
brass plug for the water jacket is located on the LH side of the cylinder head beneath the exhaust manifold
assembly.
ProCarManuals.com