cooling LAND ROVER DEFENDER 1996 Owner's Guide

41TRANSFER GEARBOX
2
REPAIR
11.Remove 3 trim studs and lift up handbrake
gaiter.
12.Remove split pin, clevis pin, washer and
disconnect cable from handbrake lever. Ensure
handbrake is off.
13.Release handbrake outer cable from heelboard.
14.Remove fan cowl
See COOLING SYSTEM,
Repair, Fan cowl
.
15.Raise vehicle on ramp.
16.Drain transfer box oil
See SECTION 10,
Maintenance, Under vehicle maintenance
.
17.Remove intermediate silencer.
See MANIFOLD
AND EXHAUST SYSTEM, Repair,
Intermediate pipe - 90
orSee MANIFOLD
AND EXHAUST SYSTEM, Repair,
Intermediate pipe - 110/130
.
18.Mark rear propeller shaft drive flange and
transmission brake drum for reassembly.
19.Remove 4 nuts, disconnect propeller shaft from
brake drum, and tie aside.
20.Mark front propeller shaft drive flange and
transfer box output flange for reassembly.
21.Remove 4 nuts, disconnect propeller shaft from
transfer box, and tie aside.
22.Remove retaining clip at lower end of pivot arm
and disconnect differential lock control operating
rod.

STEERING
7
REPAIR POWER STEERING PUMP
Service repair no - 57.20.14
Remove
NOTE: A chassis undertray may be fitted
on some vehicle derivatives to conform to
legal requirements. When under chassis
remove and refit procedures are required, it may
be necessary to remove the undertray
See
CHASSIS AND BODY, Repair, Front undertray
.
1.Disconnect battery.
2.Remove viscous fan unit
See COOLING
SYSTEM, Repair, Viscous coupling and fan
.
3.Restrain steering pump pulley, slacken but do
not remove 3 bolts securing pulley.
4.Remove drive belt
See ELECTRICAL, Repair,
Auxiliary drive belt
.
5.Remove bolts and remove pulley.
6.Position suitable container beneath steering
pump.
7.Slacken retaining clip and disconnect return
hose from steering pump.
8.Disconnect high pressure pipe from steering
pump.
9.Allow steering fluid to drain into container.
CAUTION: Plug all connections to prevent
ingress of dirt.
10.Remove 4 bolts securing steering pump bracket
to engine auxiliary mounting bracket.
11.Remove pump and bracket assembly.
12.Remove 3 bolts and detach mounting bracket
from pump.
Refit
13.Fit mounting bracket to replacement steering
pump. Tighten bolts to
9 Nm (7 lbf/ft).
14.Fit pump and bracket to auxiliary mounting
bracket. Tighten bolts to
35 Nm (26 lbf/ft).
15.Connect high pressure feed pipe to steering
pump and tighten to
20 Nm (15 lbf/ft).
16.Connect return hose to steering pump. Tighten
retaining clip to
3 Nm (2 lbf/ft).
17.Position pulley to steering pump, coat threads of
bolts with Loctite 242; fit but do not fully tighten
bolts.
18.Fit drive belt
See ELECTRICAL, Repair,
Auxiliary drive belt
.
19.Restrain steering pump pulley, tighten bolts to
10
Nm (7lbf/ft).
20.Fit viscous fan unitSee COOLING SYSTEM,
Repair, Viscous coupling and fan
.
21.Bleed power steering system
See Power
steering system - bleed
.
POWER STEERING PUMP DRIVE BELT
Service repair no - 57.20.02
NOTE: For details of drive belt remove and
refit
See ELECTRICAL, Repair, Auxiliary
drive belt
.

80HEATING AND VENTILATION
2
DESCRIPTION AND OPERATION HEATER OPERATION
The heater matrix (3), located in the distribution unit
(1), see J6341, is connected to the engine cooling
system. As water is circulated continuously through
the matrix, a selection of heated or ambient air is
controlled by two flaps within the distribution unit. The
temperature flap (12) controls the amount of ambient
air to the heater matrix, air being suppliedthrough a ducted vent on top of the vehicle front wing
to the blower motor (volute) housing (4). The blower
motor (10) can be used to boost the air flow into the
distribution unit. The air flap (13) controls the supply of
heated or ambient air from the heater unit into a
plenum chamber integeral with the vehicle fascia. Two
flaps in the plenum chamber (heater duct) distribute
the air flow to either the footwell vents or windscreen
demister vents as shown.
HEATER CONTROLS
1. Temperature control
Move the lever downwards to increase air
temperature or up to decrease air temperature.
2. Air distribution control
Lever fully up - windscreen vents only.
Lever midway - footwell and windscreen vents.
Lever fully down - footwell vents.3. Blower motor fan speed control
Move the lever progressively downwards to increase
fan speed. With the control at '0' the fan is switched
off and the volume of air entering the passenger
compartment is solely dependent on ram air when the
vehicle is moving.

HEATING AND VENTILATION
1
REPAIR HEATER UNIT
Service repair no - 80.20.01
Remove
1.Remove bonnet and disconnect battery.
2.Remove radiator bottom hose at radiator union
and drain cooling system
See COOLING
SYSTEM, Repair, Drain and refill cooling
system
.
3.Slacken clips and remove heater hoses at
heater box unions.
4.Remove outer cable securing clips.
5.Slacken trunnions and remove control cables
from heater vent flap levers.
6.Remove heater wiring harness securing loop.
7.Disconnect harness multi-plug.
8.Remove interior bulkhead trim.
9.Remove lower nuts and bolts securing the
heater unit to the bulkhead.
10.Slacken heater unit upper retaining bolts.
11.Manoeuvre heater unit, complete with blower
motor, clear of air inlet duct and remove from
engine compartment.
12.If existing heater unit is to be refitted, remove
sealing rubber.
For heater matrix removal
See Heater matrix.
For blower motor removal
See Blower motor.
Refit
13.Smear a new heater unit sealing rubber with a
suitable impact adhesive and fit to heater.
14.Manoevre heater unit into position in engine
compartment, fit blower motor to air inlet duct
and locate upper fixing bolts.
15.Loosely fit heater unit lower fixing bolts.
16.Fully tighten upper fixing bolts.
17.Fully tighten lower fixings and refit interior
bulkhead trim.
18.Secure wiring harness and reconnect multi-plug.
19.Fit control cables to vent flap trunnions and
secure with outer cable clips.
20.Connect heater hoses.
21.Fit radiator bottom hose and refill cooling system
See COOLING SYSTEM, Repair, Drain and
refill cooling system
.
22.Fit bonnet and reconnect battery.

AIR CONDITIONING
1
DESCRIPTION AND OPERATION AIR CONDITIONING SYSTEM
Description
Air conditioning is an optional system which provides
fully integrated climate control for the vehicle interior.
The air conditioning system comprises four major
units as follows:- An evaporator matrix and expansion
valve (1), housed in the heater/ cooler unit (3), an
engine mounted compressor (4), a condenser (5),mounted in front of the radiator, and a receiver/drier
(7) located to the right of the condenser.
Ancillary components in the system comprise a blower
motor (2), also housed in the heater/cooler unit, and
condenser cooling fan motors (6), mounted on a
support frame. The four major units are interconnectd
by preformed metal and flexible refrigerant pipes as
illustrated below (RH drive installation shown).
Coolant flow to a heater matrix, housed in the heater
cooler unit, is controlled by a water valve (8) from a
combined air conditioning panel on the vehicle fascia.
1.Evaporator matrix and expansion valve
2.Blower motor
3.Heater/cooler unit
4.Compressor
5.Condenser6.Condenser fan motors
7.Receiver/drier
8.Water valve
9.Heater matrix feed and return hoses

82AIR CONDITIONING
2
DESCRIPTION AND OPERATION Operation
Evaporator unit and expansion valve
High pressure liquid refrigerant is delivered to the
expansion valve which is the controlling device for the
air conditioning system. A severe pressure drop
occurs across the valve and as the refrigerant flows
through the evaporator it picks up heat from the
ambient air, boils and vaporizes. As this change of
state occurs, a large amount of latent heat is
absorbed. The evaporator is therefore cooled and as
a result heat is extracted from the air flowing across
the evaporator. The refrigerant leaves the evaporator,
on its way to the compressor, as a low pressure gas.
An evaporator sensor measures the air temperature at
the evaporator and engages or disengages the
compressor clutch to prevent icing of the air ways.
Compressor
The compressor, a pump specially designed to raise
the pressure of the refrigerant, is mounted on the front
of the engine and is driven by an independent drive
belt from the crankshaft pulley. The compressor draws
vaporized refrigerant from the evaporator. It is
compressed with a resulting rise in temperature and
passed on to the condenser as a hot, high pressure
vapour.
Condenser
The condenser is mounted directly in front of the
radiator and consists of a refrigerant coil mounted in a
series of thin cooling fins to provide the maximum
heat transfer. Air flow across the condenser is induced
by vehicle movement and assisted by two electric fans
attached to the frame of the condenser. The
refrigerant high pressure vapour enters the condenser
inlet on the RH side. As the vapour passes through
the condenser coils the air flow, assisted by the two
fans, carries the latent heat away from the condenser.
This induces a change of state resulting in the
refrigerant condensing into a high pressure warm
liquid. From the condenser, the refrigerant continues
to the receiver/ drier.
Receiver/drier
This component acts as a reservoir and is used to
hold extra refrigerant until it is needed by the
evaporator. The drier within the receiver unit contains
a filter and dessicant (drying material) which absorb
moisture and prevent dessicant dust from being
carried with the refrigerant into the system.AIR CONDITIONING AND HEATER CONTROLS -
LH DRIVE
1. Temperature control
Move the lever upwards (RED) to increase air
temperature, or downwards (BLUE) to reduce air
temperature.
2. Air conditioning switch
Press the switch (indicator lamp illuminates) to
activate the air conditioning. Press again to switch off.
3. Air recirculation control
Move the lever fully upwards to activate air
recirculation. Move the lever fully downwards to
cancel recirculation.
NOTE: Prolonged recirculation may cause
the windows to mist up.
4. Air distribution control
Lever fully up - air to windscreen vents (also provides
some air to the footwell).
Lever midway - air to fascia vents (also provides some
air to the footwell).
Lever fully down - air to footwell vents (also provides
some air to the windscreen).

82AIR CONDITIONING
6
ADJUSTMENT SYSTEM TEST
1.Place the vehicle in a ventilated, shaded area
free from excessive draught, with the doors and
windows open.
2.Check that the surface of the condenser is not
restricted with dirt, leaves, flies, etc. Do not
neglect to check the surface between the
condenser and the radiator. Clean as necessary.
3.Switch on the ignition and the air conditioner air
flow control. Check that the blower is operating
efficiently at low, medium and high speeds.
Switch off the blower and the ignition.
4.Check that the evaporator condensate drain
tubes are open and clear.
5.Check the tension of the compressor driving belt,
and adjust if necessary.
6.Inspect all connections for the presence of
refrigerant oil. If oil is evident, check for leaks,
and repair as necessary.
NOTE: The compressor oil is soluble in
Refrigerant R134a and is deposited when
the refrigerant evaporates from a leak.
7.Start the engine.
8.Set the temperature controls to cold and switch
the air conditioner blower control on and off
several times, checking that the magnetic clutch
on the compressor engages and releases each
time.
9.With the temperature control at maximum
cooling and the blower control at high speed,
warm up the engine and fast idle at 1000
rev/min.
10.Repeat at 1800 rev/min.
11.Gradually increase the engine speed to the high
range and check the sight glass at intervals.
12.Check for frosting on the service valves.
13.Check the high pressure hoses and connections
by hand for varying temperature. Low
temperature indicates a restriction or blockage at
that point.
14.Switch off the air conditioning blower and stop
the engine.
15.If the air conditioning equipment is still not
satisfactory, carry out a pressure test as
previously described in this section.PRECAUTIONS IN HANDLING REFRIGERANT
LINES
WARNING: Wear eye and hand protection
when disconnecting components
containing refrigerant. Plug all exposed
connections immediately.
1.When disconnecting any hose or pipe
connection the system must be discharged of all
pressure. Proceed cautiously, regardless of
gauge readings. Open connections slowly,
keeping hands and face well clear, so that no
injury occurs if there is liquid in the line. If
pressure is noticed, allow it to bleed off slowly.
2.Lines, flexible end connections and components
must be capped immediately they are opened to
prevent the entrance of moisture and dirt.
3.Any dirt or grease on fittings must be wiped off
with a clean alcohol dampened cloth. Do not use
chlorinated solvents such as trichloroethylene. If
dirt, grease or moisture cannot be removed from
inside the hoses, they must be replaced with
new hoses.
4.All replacement components and flexible end
connections must be sealed, and only opened
immediately prior to making the connection.
5.Ensure the components are at room temperature
before uncapping, to prevent condensation of
moisture from the air that enters.
6.Components must not remain uncapped for
longer than 15 minutes. In the event of delay, the
caps must be fitted.
7.Receiver/driers must never be left uncapped as
they contain Silica Gel crystals which will absorb
moisture from the atmosphere. A receiver/ drier
left uncapped must not be used, fit a new unit.
8.The compressor shaft must not be rotated until
the system is entirely assembled and contains a
charge of refrigerant.
9.A new compressor contains an initial charge of
refrigerant oil. The compressor also contains a
holding charge of gas when received which
should be retained by leaving the seals in place
until the pipes are re-connected.
10.The receiver/drier should be the last component
connected to the system to ensure optimum
dehydration and maximum moisture protection of
the system.

AIR CONDITIONING
5
REPAIR RECEIVER/DRIER
Service repair no - 82.17.01
Remove
1.Disconnect battery.
2.Recover refrigerant from air conditioning system
See Adjustment, Refrigerant recovery,
recycling, recharging.
3.Remove 6 screws and lift grille panel from
vehicle.
4.Disconnect receiver/drier dual pressure switch
multi-plug.
5.Disconnect high pressure pipe at receiver/drier.
6.Disconnect bottom union at condenser.
7.Remove retaining bolts and open clamps.
8.Release receiver/drier from condenser and
discard. It is NOT recommended to refit old unit.
9.Discard all pipe connection 'O' rings. Cap or plug
all connections to prevent ingress of dirt and
moisture.
Refit
10.Coat unions, threads and new 'O' rings with
refrigerant oil prior to reassembly.
11.Secure new receiver/drier in retaining clamp.
12.Fit receiver/drier bottom union connector at
condenser.
13.Fit high pressure pipe to receiver/drier.
14.Fit pressure switch multi-plug.
15.Evacuate and recharge air conditioning system
See Adjustment, Refrigerant recovery,
recycling, recharging.
16.Reconnect battery.
17.Fit grille panel assembly.HEATER/COOLER UNIT - LH DRIVE
Service repair no - 82.25.21
Remove
1.Disconnect battery.
2.Recover refrigerant from air conditioning system
See Adjustment, Refrigerant recovery,
recycling, recharging.
3.Remove expansion tankSee COOLING
SYSTEM, Repair, Expansion tank
to gain
access to air conditioning high and low pressure
pipes.
4.Disconnect high and low pressure pipes. Discard
pipe connection 'O' rings. Cap or plug
connections to prevent ingress of dirt and
moisture.
5.Disconnect compressor clutch switch multi-plug.
6.Remove pipe connector from vacuum switch.
7.Remove retaining clip and disconnect control
cable from evaporator flap operating rod.
8.Remove screw and release outer cable retaining
bracket.

82AIR CONDITIONING
6
REPAIR 9.Remove plug connector from resistor.
10.Remove relay from connecting block to gain
access to fixing screw.
11.Remove screw and release relay connector
block. Retain relay in connector block.
12.Remove screw and detach air conditioning 30
amp fuse bracket from resistor. Refit both
resistor retaining screws.
13.Using suitable pipe clamps, clamp heater matrix
feed and return hoses at base of heater/cooler
unit. Release retaining clips and remove hoses.
14.From inside vehicle remove front passenger
carpet, if fitted.
15.Remove retaining screws and fold back footwell
insulation.
16.Remove 2 bolts securing heater/cooler unit lower
mounting bracket to bulkhead.
17.From inside engine compartment remove 2 bolts
securing top heater/cooler unit mounting bracket
to engine bulkhead. This also releases earthing
leads.
18.Remove bolt securing support bracket to front of
heater/cooler casing.19.Lift heater/cooler unit clear of air duct seal and
remove from vehicle.
20.Discard all pipe connection 'O' rings.
Refit
21.Coat unions, threads and new 'O' rings with
refrigerant oil prior to reassembly.
22.Position heater/cooler unit in engine
compartment and locate with air duct seal.
23.Secure unit top and bottom mounting brackets to
bulkhead and support bracket to front of unit
casing. Fully tighten fixing bolts when unit is
correctly positioned.
24.Fit footwell insulation.
25.Reconnect heater matrix hoses.
26.Fit air conditioning fuse bracket, relay connector
block, relay and resistor plug connector.
27.Fit control cable to evaporator air flap operating
rod, using a new clip.
28.Fit pipe connector to vacuum switch.
29.Connect compressor clutch switch multi-plug.
30.Connect high and low pressure pipes to
evaporator.
31.Fit expansion tank
See COOLING SYSTEM,
Repair, Expansion tank.
32.Evacuate and recharge air conditioning system
See Adjustment, Refrigerant recovery,
recycling, recharging.
33.Reconnect battery.

86ELECTRICAL
12
REPAIR AUXILIARY DRIVE BELT
Service repair no - 86.10.03
NOTE: If cast lines on tensioner arm and
tensioner spring case are aligned, a new
drive belt must be fitted.
Remove
1.Disconnect battery.
2.Remove fan cowl
See COOLING SYSTEM,
Repair, Fan cowl.
3.Apply ring spanner to tensioner pulley retaining
bolt.
4.Turn spanner to release pulley tension from belt.
5.Detach belt from pulley.
6.Release tensioner.
7.Complete removal of belt. Mark direction on belt
if refitting.
Refit
8.Using ring spanner, release pulley tensioner and
fit new drive belt.
9.Remove ring spanner, drive belt will
automatically tension.
10.Fit fan cowl
See COOLING SYSTEM, Repair,
Fan cowl.
STARTER MOTOR
Service repair no - 86.60.01
Remove
1.Disconnect battery.
2.Disconnect electrical leads from starter solenoid.
3.Remove 3 fixings securing starter motor to
flywheel housing.
4.Withdraw starter motor.
Refit
5.Locate starter motor and secure to flywheel
housing.
6.Reconnect electrical leads to starter solenoid.
7.Reconnect battery.