1999 LAND ROVER DEFENDER engine oil

COOLING SYSTEM
9
DESCRIPTION AND OPERATION Viscous Fan
1.Idler pulley drive attachment
2.Fan blades3.Bi-metallic coil
4.Body
The viscous fan provides a means of controlling the speed of the fan relative to the operating temperature of the
engine. The fan rotation draws air through the radiator, reducing engine coolant temperatures when the vehicle is
stationary or moving slowly.
The viscous fan is attached to an idler pulley at the front of the engine which is driven at crankshaft speed by the
auxiliary drive belt. The fan is secured to the pulley by a right hand threaded nut. The nut is positively attached to
the fan spindle which is supported on bearings in the fan body. The viscous drive comprises a circular drive plate
attached to the spindle and driven from the idler pulley. The drive plate and body have interlocking annular
grooves with a small clearance which provides the drive when silicone fluid enters the fluid chamber. A bi-metallic
coil is fitted externally on the forward face of the body. The coil is connected to and operates a valve in the body.
The valve operates on a valve plate with ports that connect the reservoir to the fluid chamber. The valve plate also
has return ports which, when the valve is closed, scoop fluid from the fluid chamber and push it into the reservoir
under centrifugal force.
Silicone fluid is retained in a reservoir at the front of the body. When the engine is off and the fan is stationary, the
silicone fluid level stabilises between the reservoir and the fluid chamber. This will result in the fan operating when
the engine is started, but the drive will be removed quickly after the fan starts rotating and the fan will’freewheel’.
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26COOLING SYSTEM
10
DESCRIPTION AND OPERATION At low radiator temperatures, the fan operation is not required and the bi-metallic coil keeps the valve closed,
separating the silicone fluid from the drive plate. This allows the fan to’freewheel’reducing the load on the engine,
improving fuel consumption and reducing noise generated by the rotation of the fan.
When the radiator temperature increases, the bi-metallic coil reacts and moves the valve, allowing silicone fluid to
flow into the fluid chamber. The resistance to shear of the silicone fluid creates drag on the drive plate and
provides drive to the body and the fan blades.
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COOLING SYSTEM
11
DESCRIPTION AND OPERATION OPERATION
Coolant Flow - Engine Warm Up
During warm up the coolant pump moves fluid through the cylinder block and it emerges from the outlet housing.
From the outlet housing, the warm coolant flow is prevented from flowing through the upper and lower radiators
because both thermostats are closed. The coolant is directed into the heater circuit.
Some coolant from the by-pass pipe can pass through small sensing holes in the flow valve. The warm coolant
enters a tube in the thermostat housing and surrounds 90% of the thermostat sensitive area. Cold coolant
returning from the radiator bottom hose conducts through 10% of the thermostat sensitive area. In cold ambient
temperatures the engine temperature can be raised by up to 10°C (50°F) to compensate for the heat loss of the
10% exposure to the cold coolant return from the radiator bottom hose.
At engine speeds below 1500 rev/min, the by-pass valve is closed only allowing the small flow through the sensing
holes. As the engine speed increases above 1500 rev/min, the greater flow and pressure from pump overcomes
the light spring and opens the by-pass flow valve. The flow valve opens to meet the engine’s cooling needs at
higher engine speeds and prevents excess pressure in the cooling system. With both thermostats closed,
maximum flow is directed through the heater circuit.
The heater matrix acts as a heat exchanger reducing the coolant temperature as it passes through the matrix.
Coolant emerges from the heater matrix and flows to the fuel cooler’T’connection via the heater return hose.
From the fuel cooler the coolant is directed into the coolant pump feed pipe and recirculated around the heater
circuit. In this condition the cooling system is operating at maximum heater performance.
Coolant Flow - Engine Hot
As the coolant temperature increases the main thermostat opens. This allows some coolant from the outlet
housing to flow through the top hose and into the radiator to be cooled. The hot coolant flows from the left tank in
the radiator, along the tubes to the right tank. The air flowing through the fins between the tubes cools the coolant
as it passes through the radiator.
A controlled flow of the lower temperature coolant is drawn by the pump and blended with hot coolant from the
by-pass and the heater return pipes in the pump feed pipe. The pump then passes this coolant, via the cylinder
block, to the oil cooler housing, cooling the engine oil before entering the block to cool the cylinders.
When the fuel temperature increases, the heat from the fuel conducts through the fuel cooler’T’connection and
causes the fuel thermostat to open. Coolant from the cylinder block flows through the oil cooler and via a pipe and
hose enters the lower radiator. The lower temperature coolant from the oil cooler housing is subjected to an
additional two passes through the lower radiator to further reduce the coolant temperature. From the lower radiator
the coolant flows , via a hose, to the fuel cooler.
As the hot fuel cools, travelling slowly forwards through the cooler, it meets the progressively colder coolant
travelling in the opposite direction from the lower radiator.
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26COOLING SYSTEM
12
DESCRIPTION AND OPERATION Viscous Fan Operation
A = Cold
B = Hot
1.Drive plate
2.Fan body
3.Clearance
4.Valve plate
5.Valve
6.Bi-metallic coil7.Fluid seals
8.Ball race
9.Fluid chamber
10.Reservoir
11.Return port
When the engine is off and the fan is not rotating, the silicone fluid stabilises within the fluid chamber and the
reservoir. The fluid levels equalise due to the return port in the valve plate being open between the fluid chamber
and the reservoir. In this condition, when the engine is started, silicone fluid is present in the fluid chamber and
causes drag to occur between the drive plate and the body. This causes the fan to operate initially when the
engine is started.
As the fan speed increases, centrifugal force and a scoop formed on the fluid chamber side of the valve plate,
pushes the silicone fluid through the return port in the valve plate into the reservoir. As the fluid chamber empties,
the drag between the drive plate and the body is reduced, causing the drive plate to slip. This reduces the
rotational speed of the fan and allows it to’freewheel’.
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33CLUTCH
6
DESCRIPTION AND OPERATION DESCRIPTION
General
The clutch system is a diaphragm type clutch operated by a hydraulic cylinder. The drive plate is of the rigid centre
type with no integral damping springs. The flywheel is of the dual mass type with damping springs integral with the
flywheel. The clutch requires no adjustment to compensate for wear.
Hydraulic Clutch
The hydraulic clutch comprises a master cylinder, slave cylinder and a hydraulic reservoir. The master and slave
cylinders are connected to each other hydraulically by plastic and metal pipes. The plastic section of the pipe
allows ease of pipe routing and also absorbs engine movements and vibrations.
The master cylinder comprises a body with a central bore. Two ports in the body connect the bore to the hydraulic
feed pipe to the slave cylinder and the fluid reservoir. The bore is also connected to a damper which prevents
engine pulses being transferred hydraulically to the clutch pedal. A piston is fitted in the bore and has an external
rod which is attached to the clutch pedal with a pin. Two coil springs on the clutch pedal reduce the effort required
to depress the pedal.
The master cylinder is mounted on the bulkhead and secured with two bolts. The cylinder is connected to the
shared brake/clutch reservoir on the brake servo by a braided connecting hose.
The slave cylinder is located on the left hand side of the gearbox housing and secured with two bolts. A heat
shield is fitted to protect the underside of the slave cylinder from heat generated from the exhaust system. The
slave cylinder comprises a cylinder with a piston and a rod. A port in the cylinder body provides the attachment for
the hydraulic feed pipe from the master cylinder. A second port is fitted witha bleed nipple used for removing air
from the hydraulic system after servicing. The piston rod locates on a clutch release lever located in the gearbox
housing. The rod is positively retained on the release lever with a clip.
Clutch Mechanism
The clutch mechanism comprises a flywheel, drive plate, pressure plate, release lever and a release bearing. The
clutch mechanism is fully enclosed at the rear of the engine by the gearbox housing.
A clutch release bearing sleeve is attached in the gearbox housing with two bolts and located on two dowels. A
spigot with a ball end is formed on the release bearing sleeve and provides a mounting and pivot point for the
clutch release lever. A dished pivot washer is located on the ball of the spigot. When the release lever is located
on the ball, the pivot washer seats against the rear face of the release lever. A spring clip is located on the lever
and the pivot washer and secures the lever on the spigot. A small bolt retains the spring clip in position.
The release lever is forked at its inner end and locates on the clutch release bearing carrier. The outer end of the
release lever has a nylon seat which locates the slave cylinder piston rod. A second nylon seat, positioned
centrally on the release lever, locates on the ball spigot of the release bearing sleeve and allows the release lever
to pivot freely around the ball.
The clutch release bearing locates on the clutch release lever and release bearing sleeve. The bearing is retained
on a carrier which has two flats to prevent the carrier rotating on the release lever. A clip retains the release lever
on the carrier. The bearing and carrier are not serviceable individually.
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33CLUTCH
8
DESCRIPTION AND OPERATION The dual mass flywheel is bolted on the rear of the crankshaft with eight bolts. A dowel on the crankshaft flange
ensures that the flywheel is correctly located. A ring gear is fitted on the outer diameter of the flywheel. The ring
gear is not serviceable. Thirty blind holes are drilled in the outer diameter of the flywheel adjacent to the ring gear.
The holes are positioned at 10°intervals with four 20°spaces. The holes are used by the crankshaft position
sensor for engine management.
The dual mass flywheel is used to insulate the gearbox from torsional and transient vibrations produced by the
engine. The flywheel comprises primary and secondary flywheels with the drive between the two transferred by a
torsional damper which comprises four coil springs. The springs are located in the inside diameter of the primary
flywheel. Two of the springs are of smaller diameter and fit inside the larger diameter springs.
The primary flywheel locates the ring gear and is attached to the crankshaft flange with eight bolts. The two pairs
of coil springs are located in a recess in the flywheel between two riveted retainers. A roller bearing is pressed
onto the central boss of the primary flywheel and retained with a riveted plate. The bearing provides the mounting
for the secondary flywheel.
The secondary flywheel comprises two parts; an outer flywheel which provides the friction surface for the clutch
drive plate and an inner drive plate which transfers the drive from the primary flywheel, via the coil springs, to the
outer flywheel. The two components of the secondary flywheel are secured to each other with rivets. The inner
drive plate is located between the two pairs of coil springs and can rotate on the ball bearing in either direction
against the combined compression force of the four coil springs. Under high torque loading conditions the
secondary flywheel can rotate in either direction up to 70°in relation to the primary flywheel.
The operating face of the secondary flywheel is machined to provide a smooth surface for the drive plate to
engage on. Three dowels and six studs and nuts provide for the location and attachment of the pressure plate.
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37MANUAL GEARBOX
8
REPAIR
12.Remove 13 screws securing tunnel cover.
13.Release and remove tunnel cover.
14.Remove cooling fan.See COOLING SYSTEM,
Repair.
15.Remove air filter.See FUEL SYSTEM, Repair.
16.Remove 2 upper bolts securing clutch housing to
engine.
17.Remove bolt securing shim to clutch housing.
18.Release gearbox breather pipes from clips on
heater hose.
19.Remove starter motor.See ELECTRICAL,
Repair.
20.Remove exhaust front pipe.See MANIFOLD
AND EXHAUST SYSTEM, Repair.
21.Drain gearbox oil.See Adjustment.
22.Drain transfer gearbox oil.See
MAINTENANCE ,
23.Remove 3 nuts securing intermediate silencer to
tail pipe.
24.Release silencer from mounting rubbers, remove
silencer and discard gasket.
25.Mark front and rear propeller shaft to transfer
gearbox flanges for reassembly purposes.
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MANUAL GEARBOX
11
REPAIR Refit
44.Clean gearbox to engine mating faces, dowels
and dowel holes.
45.With assistance raise gearbox on jack and align
to clutch and engine.
46.Fit lower bolts securing clutch housing to engine
and tighten to50 Nm (37 lbf.ft).
NOTE: Do not fit upper bolts at this stage.
47.Fit earth leads and secure with bolt.
48.Connect Lucars to differential lock switch,
multiplug to reverse light switch, position
multiplug to bracket and connect low ratio detect
multiplug - if fitted.
49.Raise gearbox jack and guide transfer gearbox
lever through tunnel.
50.Secure body harness clips to bracket on top of
transfer gearbox.
51.Position battery earth lead to transfer gearbox
and tighten retaining nut.
52.Connect multiplug to speed sensor and secure
harness in clip on transfer gearbox.
53.Position mounting brackets and rubber
mountings, positioning heat shield to LH
mounting and tighten bracket bolts to85 Nm (63
lbf.ft).
54.Position nuts to mountings and tighten to48 Nm
(35 lbf.ft).
55.Remove 3 bolts securing support plate
LRT-99-007to gearbox.
56.Position handbrake cable through heel board.
57.Position clutch slave cylinder, fit bolts and
tighten to25 Nm (18 lbf.ft).
58.Clean propeller shafts and mating faces.
59.Position propeller shafts, align to marks and
tighten nuts to48 Nm (35 lbf.ft).
60.Clean intermediate silencer and tail pipe mating
faces.
61.Position silencer and secure on mountings,
using a new gasket align to tail pipe, fit nuts and
tighten to25 Nm (18 lbf.ft).
62.Refill gearbox with oil.See Adjustment.
63.Refill transfer gearbox with oil.See
MAINTENANCE ,
64.Fit exhaust front pipe.See MANIFOLD AND
EXHAUST SYSTEM, Repair.
65.Refit starter motor.See ELECTRICAL, Repair.
66.Fit bolt securing shim plate to clutch housing and
tighten10 Nm (7 lbf.ft).
67.Position heater pipe to gearbox housing, fit
upper bolts securing clutch housing to engine
and tighten to50 Nm (37 lbf.ft).
68.Position gearbox breather pipes to clips on
heater hose.69.Fit air cleaner.See FUEL SYSTEM, Repair.
70.Fit cooling fan.See COOLING SYSTEM,
Repair.
71.Fit and align tunnel cover, fit and tighten screws.
72.Position relay panel, fit spacers and tighten
screws.
73.Position hand-brake lever and tighten bolts to25
Nm (18 lbf.ft).
74.Connect handbrake cable to lever, fit clevis pin,
washer and new split pin.
75.Connect Lucar to hand-brake switch.
76.Position gaiter to handbrake lever and secure
with trim stud.
77.Locate insulation pad over gear levers and fit to
tunnel cover.
78.Align spline marks, fit gear lever to lower lever,
fit washer and secure with retaining nut.
79.Position gear lever cover.
80.Position gearbox tunnel carpet.
81.Fit gear lever and transfer gear lever knobs.
82.Reconnect battery negative lead.
83.Fit battery cover.
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