engine LAND ROVER DEFENDER 1996 Workshop Manual

HEATING AND VENTILATION
7
REPAIR Refit
14.Fit new control cable through heater duct cover
and secure to vent flap trunnion. Bend over
cable end to fully secure.
15.Fit heater duct cover.
16.Fit lower fascia panel assembly to fascia
bulkhead
See CHASSIS AND BODY, Repair,
lower fascia panel (heater duct) assembly.
17.Route control cable along fascia bulkhead to
contol lever assembly.
18.With control lever in closed position, secure
cable to clevis.
19.Fit outer cable retaining clip to lever assembly.
20.Fit lever assembly to side cover. Ensure screw
spacers are fitted between cover and lever
assembly.
21.Fit side cover to fascia cowl.
22.Fit control lever knobs.
23.Fit instrument panel
See INSTRUMENTS,
Repair, Instrument panel.
24.Fit steering column nacelleSee STEERING,
Repair, Steering column nacelle.
CONTROL CABLE AND BLOWER MOTOR SWITCH
Service repair no - 80.10.17 - Control cable
Service repair no - 80.10.22 - Blower motor switch
Remove
1.Disconnect battery.
2.From inside engine compartment, release outer
cable retaining clip at heater unit.
3.Slacken trunnion fixing and release inner cable
from heater unit flap lever.
4.Release 2 retaining clips securing control cables
to engine bulkhead and heater hoses.
5.Remove 4 screws securing instrument panel to
fascia cowl.
6.Pull instrument panel away from fascia and
disconnect speedometer cable to ease access to
control cable.
7.Remove 2 screws securing control lever
assembly to side of fascia panel cowl. Note
plastic screw spacers fitted between cowl and
lever assembly and retain.

80HEATING AND VENTILATION
8
REPAIR
8.Release lever assembly and disconnect 3
blower motor leads, noting their positions.
9.Pull control cable through bulkhead grommet
and out from instrument panel cowl.
10.Release retaining clip securing outer cable to
lever assembly.
11.Release inner cable from lever peg.
NOTE: If the blower motor switch is faulty
the complete lever assembly will have to
be renewed.
Refit
12.Fit new control cable to lever assembly peg.
13.Fit retaining clip to secure outer cable.
14.Reconnect blower motor leads.
15.Route cable to rear of instrument panel cowl,
along bulkhead and out through grommet into
engine compartment.
16.Fit lever assembly to panel cowl. Ensure screw
spacers are fitted between cowl and lever
assembly.
17.Fit instrument panel to fascia cowl.
18.With lever in closed position, fit control cable to
heater unit flap lever trunnion.
19.Secure outer cable with retaining clip.
20.Secure control cables to engine bulkhead and
heater hoses with retaining clips.
21.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).

AIR CONDITIONING
3
DESCRIPTION AND OPERATION 5. Blower motor fan speed control
Move the lever to the right to progressively increase
fan speed.
Location of air vents - LH drive
AIR CONDITIONING AND HEATER CONTROLS -
RH DRIVE
1. Temperature control
Move the lever to the right (RED) to increase air
temperature, or to the left (BLUE) to reduce air
temperature.
2. Air conditioning indicator lamp
Illuminates when the air conditioning system is
operating.3. Air conditioning switch
Press the RH portion of the switch to activate the air
conditioning (indicator lamp illuminates). Press the LH
portion to switch off.
NOTE: Air conditioning should only be
activated when the engine is running.
4. Blower motor fan speed control
Move the lever upwards to progressively increase fan
speed.

82AIR CONDITIONING
4
ADJUSTMENT 5.Operate the refrigerant recharging system
according to the manufactures instructions.
Refrigerant to charge system is 1.1 kg.
6.If the full charge has not been accepted by the
system, start the engine and run it at 1500
rev/min for a minimum of 2 minutes.
Switch on the air conditioning system, open the
vehicle windows, set the temperature control to
cold and switch the blower to maximum speed.
7.Consult Refrigerant Station Manual for correct
procedure to complete the charge.
8.Carry out the air conditioning system
performance test.LEAK TEST SYSTEM
The following instructions refer to an electronic type
Refrigerant Leak Detector for use with R134a, which
is the safest and most sensitive.
CAUTION: When a major repair has been
carried out, a leak test should be carried
out using an inert gas (see below).
1.Place the vehicle in a well ventilated area but
free from draughts, as leakage from the system
could be dissipated without detection.
2.Follow the instructions issued by the
manufacturer of the particular leak detector
being used.
3.Commence searching for leaks by passing the
detector probe around all joints and components,
refrigerant gas is heavier than air.
4.Insert the probe into an air outlet of the
evaporator or into the evaporator drain tube.
Switch the air conditioning blower on and off at
intervals of ten seconds. Any leaking refrigerant
will be gathered in by the blower and detected.
5.Insert the probe between the magnetic clutch
and compressor to check the shaft seal for
leaks.
6.Check all service valve connections, valve plate,
head and base plate joints and back seal plate.
7.Check the condenser for leaks at the pipe
unions.
8.If any leaks are found, the system must be
discharged before rectification.
9.Rectify any leaks and recheck for leaks during
evacuation prior to charging.
Leak test using inert gas
Use Nitrogen or Helium gas.
1.Connect gas line to recharging station.
2.Pressurise system to 3 bar.
3.Carry out leak test as above.

AIR CONDITIONING
5
ADJUSTMENT AIR CONDITIONING SYSTEM - PERFORMANCE
TEST
WARNING: R134a is hazardousSee
Repair, General Precautions
Carry out this test with bonnet and doors or windows
open, air conditioning switched on, temperature
control set to cold and blower at maximum speed. Set
the air supply control to supply fresh air.
1.Close low pressure valve on refrigerant station.
2.Close high pressure valve on refrigerant station.
3.Connect a Refrigerant Station to the high and
low pressure servicing connections.4.Insert dry bulb thermometer into cold air outlet
and position dry and wet bulb thermometer close
to outside air inlet.
Do not spill water from the wet thermometer
(psychrometer).
5.Start engine and run it at 1500 rev/min for 10
minutes with air conditioning switched on.
6.Read both pressure gauges and thermometers.
Check readings against table below with
humidity between 60% and 80%.
7.Switch off air conditioning, stop engine,
disconnect test equipment.
Performance range
Intake temperature Outlet temperature Low pressure High pressure
20 - 24°C4-10°C 18 - 28 lbf/in
2213 - 299 lbf/in2
1.2 - 1.9 bar 14.7 - 20.6 bar
25 - 29°C9-19°C 27 - 37 lbf/in2256 - 341 lbf/in2
1.9 - 2.6 bar 17.6 - 23.5 bar
30 - 35°C20-27°C 33 - 47 lbf/in2299 - 384 lbf/in2
2.3 - 3.2 bar 20.6 - 26.5 bar
Table 1
Ambient Compound Gauge High Pressure
Temperature Readings Gauge Readings
°C°F bar lbf/in
2bar lbf/in2
16 60 1,03-1,4 15-20 6,9-10,3 100-150
26,7 80 1,4-1,72 20-25 9,6-13,1 140-190
38 100 1,72-2,1 25-30 12,4-15,5 180-225
43,5 110 2,1-2,4 30-35 14,8-17,2 215-250

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.

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.

82AIR CONDITIONING
8
REPAIR
13.Remove all other fixings securing evaporator
and heater matrix support frame to unit casing.
14.Lift evaporator and heater matrices, complete
with support frame assembly, clear of casing.
Retain heater matrix pipe seal pad.
15.Remove 4 screws securing evaporator matrix to
support frame.
16.Withdraw evaporator matrix, complete with
expansion valve, from support frame.
17.Clean sealing compound from all joints of main
casing, top cover and outlet duct.
NOTE: The evaporator matrix is supplied
complete with the expansion valve.
However, a faulty expansion valve can be
serviced separately,
See Expansion valve.
Refit
18.Fit evaporator matrix in support frame.
19.Fit evaporator, heater matrix and support frame
assembly in casing. Ensure studs for lower
mounting bracket are located through bottom of
casing.
20.Apply mastic sealant around heater matrix pipes
to seal pipe apertures in casing. Fit seal pad
over pipes.
21.Fit 3 bottom fixings to secure to secure base of
support frame.
22.Fit all other fixings to secure support frame
assembly.
23.Locate heater matrix insulation pad and cover
plate.
24.Apply sealng compound around top edge of
main casing.
25.Feed blower motor wiring through top cover and
fit grommet.
26.Fit top cover to casing. Ensure thermostat
temperature probe is inserted in top of
evaporator. Apply mastic sealant to air flap
operating rod aperture.
27.Apply sealing compound to joint face of blower
motor outlet duct.
28.Locate duct over blower motor outlet and secure
to casing.
29.Secure lower mounting bracket to retaining studs
on base of main casing.
30.Fit heater/cooler unit assembly in engine
compartment
See Heater/cooler unit.