lock LAND ROVER DISCOVERY 2002 Repair Manual

ENGINE - TD5
12-1-18 DESCRIPTION AND OPERATION
Oil filter housing thermostat
1Circlip
2Thermostat end cap
3Oil seal
4Thermostatic valve
5Return spring
6Oil filter housing
7Threaded 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 following table indicates approximate values for thermostat plunger travel against temperature:
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 psi) is experienced.
Thermostat plunger travel mm (in.) Oil temperature °C
0 (0) < 74 °C
5 (0.20) 80 °C
12 (0.47) 90 °C
16 (0.63) 130 °C

ENGINE - TD5
DESCRIPTION AND OPERATION 12-1-19
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.
Crankshaft, sump and oil pump components
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.
The 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.

ENGINE - TD5
12-1-20 DESCRIPTION AND OPERATION
Oil pump
1Stiffener plate
2Ring dowel
3Outlet port
4Outer rotor
5Inner rotor6Spring dowel
7Oil pressure relief valve cap
8Oil pressure relief valve spring
9Oil pressure relief valve plunger
10Inlet 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.

ENGINE - TD5
DESCRIPTION AND OPERATION 12-1-21
Crankshaft
1Front end to crankshaft sprocket
2Oil supply cross-drillings
3Main journals
4Big-end journals
5Rear 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.
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 model 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.

ENGINE - TD5
12-1-22 DESCRIPTION AND OPERATION
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 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.

ENGINE - TD5
DESCRIPTION AND OPERATION 12-1-23
Fuel connector block
A = Pre EU3 models, B = EU3 models
1Fuel connector block assembly
2Outlet stub pipe
3Stub pipe – to fuel cooler
4Fuel temperature sensor
5Fuel pressure regulator
6Spill fuel return connection (EU3 models only)
A cast and machined alloy fuel connector block assembly is located at the rear RH side of the cylinder head, attached
by three flanged bolts. A metal gasket is used to seal the faces between the fuel connector block and the cylinder
head, which must be replaced every time the fuel connector block is removed.
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.
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.
Camshaft carrier
The cast aluminium alloy camshaft carrier is bolted to the cylinder head by thirteen screws. 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.
The carrier is machined together with the cylinder head to form a matched pair for carrying the camshaft.
Non-return valve
A non-return valve is located at the front, bottom LH side of the cylinder head. The non-return valve prevents oil from
draining from the lash adjusters and is an integral component within the cylinder head and is non-serviceable.

ENGINE - TD5
12-1-24 DESCRIPTION AND OPERATION
Camshaft
The camshaft is machined from cast steel and is located between the cylinder head and the camshaft carrier, and the
six bearing journals are line bored between the two components to form a matched pair. The machined camshaft has
15 lobes. Ten lobes operate the inlet and exhaust valves through hydraulic lash adjusters and finger followers which
are located below the camshaft. Five larger lobes activate the injector rockers which are located above the camshaft
on the rocker shaft and are used to generate fuel pressure in the EUI injectors.
The camshaft is sprocket driven via a duplex chain connected to the crankshaft sprocket at a speed ratio of 2:1. The
camshaft sprocket is fixed to the front end of the camshaft by three bolts.
Camshaft lubrication is splash and channel fed via pressurised oil flowing through galleries in the cylinder head.
Rocker shaft and Rocker Arms
A = Pre EU3 rocker arm, B = EU3 rocker arm
1Rocker shaft
2Rocker arm adjusting screw
3Rocker arm
4EUI pin and roller assembly
5Roller pin retention slug6Camshaft lobe
7Injector spring
8Injector push-rod
9Adjusting nut
The hollow rocker shaft is located in the camshaft carrier in six fixed mountings which sit above the camshaft. Six bolts
are used to lock the rocker shaft to the camshaft carrier. The front rocker shaft bearing has a ring dowel located at the
front rocker shaft mounting of the camshaft carrier for rocker shaft alignment. Two circlips hold each rocker arm in
position at the relevant positions on the rocker shaft.
The rocker shaft from a pre EU3 model must not be fitted to an EU3 engine. This is because the stroke of the
EU3 injector has increased which requires the rocker to articulate over a larger angle.
The camshaft end of each rocker arm features a roller which is free to rotate about a pin which passes through two
webs in the rocker arm, the roller pins are held in place by an interference fit retention slug passing through a hole in
the front web of each rocker arm.
To correctly function against the higher injection loads of the EU3 engine the geometry of the contact between the
injector pushrod and rocker arm adjusting screw has been modified. Both designs of adjusting screw are separately
available with the EU3 version being identified by an engraved dimple in the slotted end.
Rocker shaft and rocker arm lubrication is splash and channel fed via pressurised oil flowing through galleries in the
cylinder head and through the rocker shaft.

ENGINE - TD5
DESCRIPTION AND OPERATION 12-1-25
Inlet and exhaust valves
The inlet and exhaust valves are mounted directly above the engine block cylinders.
Each valve is a forged and ground solid one-piece head and stem which is hardened by heat treatment. The stems
are chrome-plated then ground for improved heat transfer, wear resistance and smooth operation. It is not possible
to recut the valve's face angle, but the valves can be lapped to their seats using grinding paste.
The valve springs are made from spring steel and are of the parallel single-coil type. The bottom end of the spring
rests on the flange of a spring seal which has a centre bore that locates on a recess ground into the lower valve stem.
The top end of the spring is held in place by a spring retainer which is held in position at the top end of the valve stem
by split taper collets. The taper collets have grooves on the internal bore that locate to grooves ground into the upper
stems of the valves.
The valve seats and valve guides are sintered and are interference fit into the cylinder head. The valve seats and
guides are non-serviceable.
Finger followers and Lash adjusters
1Valve stem
2Finger follower
3Lash adjuster plunger
4Oil supply hole
5Lash adjuster body
The valves are operated through finger followers and lash adjusters, actuated by the camshaft lobes. When the
camshaft lobe presses down on the top of a finger follower roller mechanism, the respective valve is forced down
opening the effected inlet or exhaust port.
The lash adjuster body contains a plunger and two chambers for oil feed and pressurised oil. Pressurised oil is
supplied to the lash adjusters via the oil galleries in the cylinder head and through a hole in the side of the lash adjuster
body. The oil passes into a feed chamber in the lash adjuster then through to a separate pressure chamber via a one
way ball valve. Oil flow from the pressure chamber is determined by the amount of clearance between the lash
adjuster outer body and the centre plunger, oil escapes up the side of the plunger every time the lash adjuster is
operated, the downward pressure on the plunger forcing a corresponding amount of oil in the lash adjuster body to
be displaced. When the downward pressure from the camshaft and finger follower is removed (i.e. after the trailing
flank of the camshaft lobe has passed), oil pressure forces the lash adjuster's plunger up again. This pressure is not
sufficient to affect the valve operation, but eliminates the clearance between the finger follower and top of the valve
stem.

ENGINE - TD5
12-1-26 DESCRIPTION AND OPERATION
Camshaft cover and engine cover components
The camshaft cover and engine cover components are described below:
Camshaft cover
The camshaft cover is cast from aluminium alloy and is fixed to the camshaft carrier/cylinder head assembly by 13
bolts. The cover has spacers and sealing washers inserted into each of the thirteen bolt holes.
A breather hose is connected to a port at the top of the camshaft cover by means of a hose clip which vents crankcase
gases back to the air intake via a breather valve in the air intake tract, located forward of the turbocharger in the
flexible air intake duct.
A rubber seal is fitted between the camshaft cover.
An oil filler aperture is included in the top of the camshaft cover, which is sealed with a plastic cap with integral rubber
seal.
Camshaft timing chain components
The timing chain cover and timing chain components are described below:
Timing chain cover
The timing chain cover is cast and machined aluminium alloy and is attached to the cylinder head by a bolt at the RH
top of the cover and by a stud and nut at the LH top of the cover. Eight screws are used to attach the timing chain
cover to the front of the engine block. The timing cover is located to the cylinder block front face by two dowels.
A viscous fan is attached to an idler pulley at the front of the engine block. The fan bearing is located on a shaft and
held in place by a circlip and a bearing flange, the inner race of the fan bearing is an interference fit on the shaft. The
fan idler pulley is attached to the bearing hub by three bolts, and the fan itself is secured to the pulley and bearing
shaft by a left hand threaded nut.

+ COOLING SYSTEM - Td5, DESCRIPTION AND OPERATION, Description.
The front of the crankshaft passes through a hole in the lower part of the timing cover. An oil seal is pressed into a
recess in the front of the timing cover to seal the interface between the front of the crankshaft and the timing cover.
A stub pipe is fitted to the front RH side of the timing cover which is used to attach the oil drain pipe from the vacuum
pump by means of a hose and spring clip.
Timing chains
The timing chain between the camshaft and crankshaft sprockets is a duplex type, each chain having 56 links. The
timing chain is contained between a fixed plastic guide and an hydraulically adjustable plastic tensioner arm which
are attached to the front of the engine block.
To cope with higher injection loads of the EU3 engine, the timing drive between the camshaft and crankshaft has been
upgraded. This requires thicker chain links to be used, therefore, the individual pre EU3 and EU3 components are not
interchangeable.
To distinguish between the two timing chains the links are different colours. A pre EU3 chain has blue links and a EU3
chain has bronze links.
The oil pump timing chain is a single type and traverses the oil pump sprocket and the rear crankshaft sprocket.
The timing chains are oil lubricated, with oil being provided by a chain lubrication jet and from oil flow returning back
to the sump from the cylinder head. An oil hole is included at the front left hand side of the cylinder head which supplies
oil from the cylinder head oil galleries.

ENGINE - TD5
DESCRIPTION AND OPERATION 12-1-27
Timing chain guides
1Hydraulic tensioner
2Adjustable tensioner arm
3Duplex timing chain
4Camshaft sprocket
5Fixed tensioner arm
6Crankshaft sprocket
The crankshaft sprocket to camshaft sprocket timing chain is held taut by a tensioner arm acting on the slack side of
the chain. The tensioner is automatically adjusted by means of an hydraulically operated tensioner adjuster. The drive
side of the chain has a plastic guide attached to the front face of the cylinder block. The fixed guide is attached to the
front of the engine block by two bolts. The tensioner arm is fixed to the front of the cylinder block by a single pivot bolt
which allows the tensioner arm to pivot about its axis.
The adjustable tensioner arm is not interchangeable between pre EU3 and EU3 models due to a change in geometry
on the EU3 version.