low oil pressure LAND ROVER DISCOVERY 2002 Owner's Manual

ENGINE - TD5
DESCRIPTION AND OPERATION 12-1-31
Oil cooler / Filter flow (thermostat open)
1To cylinder block main gallery (from rear of oil
cooler housing)
2Oil cooler housing
3Oil pressure switch
4Full-flow filter
5Centrifuge filter6Return to sump
7Flow from oil pump (via cylinder block)
8Oil cooler matrix

ENGINE - TD5
12-1-32 DESCRIPTION AND OPERATION
When the engine temperature is below 74° C, the thermostat in the full-flow filter housing is closed and a proportion
of the oil flow to the main oil gallery is diverted to the oil cooler to supply an oil feed to the turbocharger bearings. Oil
passes through the oil cooler to the front gallery in the oil cooler housing where there is a tapping to connect the feed
pipe to the turbocharger. Oil used by the turbocharger bearings is returned to the sump through an oil drain pipe which
connects to a port in the LH side of the cylinder block.
The remainder of the oil flow leaving the full-flow filter outlet is passed into the cylinder block via a port at the rear of
oil cooler rear gallery.
When the oil temperature rises above 74
° C the thermostat in the full-flow filter adaptor housing begins to open to
allow a proportion of the oil from the full-flow filter to pass through the oil cooler before it reaches the main oil gallery
in the cylinder block. In this instance, oil supply to the turbocharger bearings is fed directly from the full-flow filter
without first passing through the oil cooler. Between 74
° C and 88° C the thermostat valve plunger opens by about
9mm to allow proportionally more oil to flow through the oil cooler before being passed to the cylinder block main oil
delivery gallery. Above 88
°C the thermostat valve continues to open by about 1mm for every 10° C increase in
temperature until the valve is fully open, when all the oil flow to the cylinder block is forced to pass to the cylinder block
via the oil cooler.
An oil pressure switch is located in a port in the rear gallery of the oil cooler housing to sense the oil pressure level
before flow enters the main oil gallery in the engine block. A warning lamp in the instrument cluster is switched on if
the oil pressure is detected as being too low.

+ INSTRUMENTS, DESCRIPTION AND OPERATION, Description.
Drillings from the cylinder block main oil gallery direct oil to the crankshaft main bearings and cross drillings in the
crankshaft direct oil to the big-end bearings. An additional five drillings in the cylinder block supply oil at reduced
pressure to the oil squirt jets for piston cooling and gudgeon pin lubrication.
Oil supply from the cylinder block is then passed to the cylinder head galleries through a non-return valve which is
included as an integral item in the lower face of the cylinder head.

ENGINE - TD5
12-1-62 REPAIRS
Valve - relief - oil pressure
$% 12.60.56
Remove
1.Remove sump gasket.

+ ENGINE - Td5, REPAIRS, Gasket -
sump.
2.Remove and discard plug from oil pump
housing.
3.Remove spring and valve.
Refit
1.Clean valve, spring and plug.
2.Clean valve seating inside oil pump housing.
3.Check valve and bore for scoring and
corrosion. Light scoring may be removed using
grade 600 emery cloth soaked in oil.
4.Check spring for distortion, check free length of
spring: Spring free length = 42.00 mm (1.65 in).
CAUTION: Renew relief valve as an
assembly.
5.Lubricate valve and seating.
6.Fit valve and spring to pump.
7.Apply Loctite 243 sealant to threads of new
plug.
CAUTION: Do not attempt to fit original
plug.
8.Fit oil pump pressure relief valve plug and
tighten to 23 Nm (17 lbf.ft).
9.Fit sump gasket.

+ ENGINE - Td5, REPAIRS, Gasket -
sump.
10.Check engine oil level, top-up if necessary.
Switch - oil pressure
$% 12.60.50
Remove
1.Remove fixings and remove engine acoustic
cover.
2.Remove 3 bolts and remove exhaust manifold
heat shield.
3.Disconnect multiplug from oil pressure switch.
4.Position container below switch to catch oil
spillage.
5.Remove oil pressure switch from oil cooler
housing.

ENGINE - TD5
REPAIRS 12-1-63
Refit
1.Clean oil pressure switch threads.
2.Fit oil pressure switch and tighten to 15 Nm (11
lbf.ft).
3.Connect multiplug to oil pressure switch.
4.Position exhaust manifold heatshield and
tighten M6 bolts to 9 Nm (7 lbf.ft) and M8 bolts
to 25 Nm (18 lbf.ft).
5.Fit and secure engine acoustic cover.
6.Top up engine oil.

+ MAINTENANCE, PROCEDURES,
Engine oil - diesel engine.
Cooler - engine oil
$% 12.60.68
Remove
1.Drain cooling system.

+ COOLING SYSTEM - Td5,
ADJUSTMENTS, Drain and refill.
2.Remove centrifuge assembly.

+ ENGINE - Td5, REPAIRS, Gasket -
centrifuge oil drain pipe.
3.Remove clutch housing bolt and release
coolant pipe from rear of engine.
4.Release clip and coolant hose from oil cooler.
5.Disconnect multiplug from oil pressure switch.
6.Remove full-flow oil filter element using a
suitable strap wrench.
7.Remove 3 bolts, remove oil filter adaptor
housing and discard gasket.
8.Remove 7 bolts, remove oil cooler and discard
gasket.
9.Remove oil pressure switch.

ENGINE - TD5
OVERHAUL 12-1-75
5.Loosen locknuts and fully unscrew rocker
adjusting screws; discard locknuts and screws.
6.Remove and discard 6 bolts securing rocker
shaft, release shaft from locating dowel and
remove shaft.
7.Using sequence shown, progressively loosen
13 bolts securing camshaft carrier to cylinder
head until valve spring pressure is released;
remove bolts. Do not discard bolts at this
stage.
8.Gently tap camshaft carrier upwards to break
sealant bond, release carrier from locating
dowels; remove carrier.
9.Remove camshaft.
10.Remove and discard camshaft rear oil seal.11.Remove finger followers and lash adjusters.
CAUTION: Store lash adjusters in their fitted
order and store upright. Maintain absolute
cleanliness when handling lash adjusters.
Failure to observe these precautions can
result in engine failure.
12.Remove and discard 5 bolts securing EUI
retainers.
13.Using tool LRT-12-154/1 remove EUI units
from cylinder head and collect retainers;
remove reaction posts. Keep components in
their fitted order.
14.Using tool LRT-12-154/4, remove and discard
sealing washer and 'O' ring from each injector
unit.
15.Support cylinder head clear of valves, use a
hollow drift and tap each spring cap to free
collets.

ENGINE - V8
DESCRIPTION AND OPERATION 12-2-5
1Core plugs
2Cylinder block
3Camshaft
4Dipstick tube, clamp and bolt
5Woodruff key
6Timing chain
7Camshaft timing gear
8Washer
9Bolt - camshaft timing gear
10Thrust plate - camshaft end-float
11Bolt - camshaft thrust plate
12Gasket - timing cover
13Timing cover
14Oil pressure switch
15Bolt
16Crankshaft front oil seal
17Oil filter element
18Crankshaft front pulley
19Washer
20Bolt - crankshaft front pulley
21Upper main bearing shell
22Upper centre main bearing shell and thrust
washer
23Crankshaft
24Woodruff key
25Crankshaft timing gear
26Lower main bearing shells
27Numbers 1, 2 and 3 main bearing caps
28Bolt - main bearing caps
29Oil pick-up pipe and strainer
30'O' ring31Bolt - oil pick-up pipe
32Gasket - sump
33Sump
34Bolt - sump
35Sump oil drain plug
36Sealing washer
37Spacer, washers and nut - oil pick-up pipe
38Number 4 main bearing cap
39Bolt - connecting rod big-end bearing cap
40Connecting rod big-end bearing shell - lower
41Connecting rod big-end bearing cap
42Number 5 - rear main bearing cap
43Cruciform seal - rear main bearing cap
44Number 5 - rear main bearing shell
45Crankshaft rear oil seal
46Crankshaft knock sensor
47Side bolt - main bearing cap
48Side Allen bolt - main bearing cap
49Dowty washers
50Connecting rod big-end bearing shell - upper
51Connecting rod
52Piston
53Gudgeon pin
54Oil control ring
55Top compression ring
562nd compression ring
57Flywheel/drive plate and starter ring gear
58Bolt - flywheel/drive plate

ENGINE - V8
12-2-6 DESCRIPTION AND OPERATION
Description
General
The V8 petrol engine is an eight cylinder, water cooled unit having two banks of four cylinders positioned at 90 degrees
to each other. The engine comprises five main castings - two cylinder heads, cylinder block, timing cover and the oil
sump, all of which are manufactured from aluminium alloy.
NAS market vehicles from 03 model year receive a 4.6 litre version of the V8 engine to replace the previous 4.0 litre
version.
Cylinder heads
The cylinder heads are fitted with replaceable valve guides and valve seat inserts with the combustion chambers
formed in the head. Each cylinder head is sealed to the cylinder block with a gasket. The exhaust manifolds are bolted
to the outside of each cylinder head whilst the inlet manifolds are located in the centre of the 'Vee' and are bolted to
the inside face of each head. Inlet and exhaust manifolds are sealed to the cylinder heads by means of gaskets.
Each cylinder has a single inlet and exhaust valve. The exhaust valves are of the 'carbon break' type, a recess on the
valve stem prevents a build-up of carbon in the valve guide by dislodging particles of carbon as the valve stem moves
up and down the guide. Inlet and exhaust valve stem oil seals are fitted at the top of each valve guide. Valve operation
is by means of rocker arms, push rods and hydraulic tappets. Each of the rocker arms is located on a rocker shaft
which is supported by means of pedestals bolted to the cylinder heads. A spring, positioned on either side of each
rocker arm, maintains the correct relative position of the arm to its valve stem. The rocker arms are operated directly
by the push rods which pass through drillings in the cylinder heads and cylinder block. The bottom end of each push
rod locates in a hydraulic tappet operated by the single, chain driven camshaft.
The rocker covers are bolted to the cylinder heads and are sealed to the heads by a rubber gasket. Stub pipes for
crankcase ventilation hose connections are fitted to each rocker cover, the pipe in the right hand cover incorporates
an oil separator. The engine oil filler cap is situated in the right hand cover.
Cylinder block and camshaft
The cylinder block is fitted with cast iron cylinder liners which are shrink fitted and locate on stops in the block. The
camshaft is positioned in the centre of the cylinder block and runs in one piece bearing shells which are line bored
after fitting. Camshaft end-float is controlled by a thrust plate bolted to the front of the cylinder block. A timing gear,
chain driven by the crankshaft timing gear is bolted to the front of the camshaft.
Crankshaft and main bearings
The crankshaft is carried in five main bearings. The upper main bearing shell locations are an integral part of the
cylinder block casting. The lower main bearing caps are bolted to the cylinder block on either side of the upper bearing
shell locations with an additional bolt being inserted into each cap from either side of the cylinder block. The rear
main bearing cap carries the crankshaft rear oil seal and is sealed to the cylinder block by means of cruciform shaped
seals in each side of the cap. Number four main bearing cap carries the stud fixing for the oil pick-up pipe. Lower
main bearing shells are plain whilst the upper shells have an oil feed hole and are grooved. Crankshaft end-float is
controlled by the thrust faces of the upper centre shell. The crankshaft timing gear is located on the front of the
crankshaft by means of a Woodruff key which is also used to drive the gear type oil pump. The flywheel/drive plate
carries the crankshaft position sensor reluctor ring and is dowel located and bolted to the flywheel.
Timing cover
The timing cover is bolted to the front of the cylinder block and is sealed to the block with a gasket. The disposable,
full flow oil filter canister is screwed on to the timing cover which also carries the oil pressure switch, oil pressure relief
valve and crankshaft front oil seal. The gear type oil pump is integral with the cover which also has an internal oilway
to direct oil from the oil cooler to the filter.
NOTE: Oil coolers are only fitted to vehicles up to VIN 756821.

ENGINE - V8
12-2-8 DESCRIPTION AND OPERATION
Lubrication
A - To oil cooler, B - From oil cooler
NOTE: The oil cooler is only fitted to vehicles up to VIN 756821.
1Rocker shaft assembly
2Hydraulic tappet
3Oil pump
4Oil filter element
5Oil pick-up pipe and strainer
6Oil pressure switch
Oil is drawn from the sump through a strainer and into the oil pump via the oil pick-up pipe. Pressurised oil from the
pump passes through the oil cooler (if fitted) mounted in front of the radiator and returns to the full flow oil filter

ENGINE - V8
DESCRIPTION AND OPERATION 12-2-9
element. Oil from the filter passes into the main oil gallery and through internal drillings to the crankshaft where it is
directed to each main bearing and to the big-end bearings via numbers 1, 3 and 5 main bearings. An internal drilling
in the cylinder block directs oil to the camshaft where it passes through further internal drillings to the hydraulic
tappets, camshaft bearing journals and rocker shafts. Lubrication to the pistons, small ends and cylinder bores is by
oil grooves machined in the connecting rods and by splash.
Oil pressure switch
The oil pressure warning light switch registers low oil pressure in the main oil gallery on the outflow side of the filter.
Whilst the engine is running and oil pressure is correct, the switch is open. When the ignition is switched on or if oil
pressure drops below the pressure setting of the switch, the switch closes and the low oil pressure warning lamp
located in the instrument pack will illuminate.
Hydraulic tappets
1Clip
2Pushrod seat
3Inner sleeve
4Upper chamber5Non-return ball valve
6Spring
7Outer sleeve
8Lower chamber
The hydraulic tappet provides maintenance free, quiet operation of the valves. This is achieved by utilizing engine oil
pressure to eliminate the clearance between the rocker arms and valve stems. When the valve is closed, engine oil
pressure present in the upper chamber, passes through the non-return ball valve and into the lower chamber. When
the cam begins to lift the outer sleeve, the resistance of the valve spring, felt through the push rod and seat, causes
the tappet inner sleeve to move downwards inside the outer sleeve. This downwards movement closes the non-return
ball valve and increases the pressure in the lower chamber sufficiently to ensure that the valve is fully opened by the
push rod. As the tappet moves off the peak of the cam, the non-return ball valve opens thereby allowing the pressure
in both chambers to equalize. This ensures that the valve will be fully closed when the tappet is on the back of the
cam.
Crankcase ventilation
A positive crankcase ventilation system is used to vent crankcase gases to the air induction system. Gases are drawn
from the left hand rocker cover to a tapping in the throttle body. An oil separator is incorporated in the hose connection
stub pipe in the right hand rocker cover, gases from this connection are drawn to a tapping in the inlet manifold.

+ EMISSION CONTROL - V8, DESCRIPTION AND OPERATION, Crankcase emission control system.

ENGINE - V8
ADJUSTMENTS 12-2-11
ADJUST ME NTS
Engine oil pressure check
$% 12.90.09.01
Check
1.Remove oil pressure switch.

+ ENGINE - V8, REPAIRS, Switch - oil
pressure.
2.Connect pressure check kit LRT-12-052C
adaptor and gauge to oil pressure switch
position on timing gear cover.
3.Check and if necessary top up engine oil.
4.Run engine at idle speed and check that oil
pressure is within limits given.

+ GENERAL DATA, Engine - V8.
5.Switch off ignition.
6.Remove pressure check kit LRT-12-052C.
7.Clean oil spillage.
8.Fit oil pressure switch.

+ ENGINE - V8, REPAIRS, Switch - oil
pressure.
Adjust
1.If engine oil pressure is below figures given,
check condition of oil pump and/or main and
big end bearings.