1995 LAND ROVER DISCOVERY clutch

AIR CONDITIONING
1
FAULT DIAGNOSIS AIR CONDITIONING FAULTS
FAULT CAUSE REMEDY
1. Incorrect voltage. 1. Check voltage.
A.2. Open or defective fuse or relay. 2. Check and replace as necessary.
BLOWER3. Loose wire connection including 3. Check system wires; tighten
MOTORground. all connections.
INOPERATIVE4. Switch open or defective. 4. Replace switch.
OR SLOW5. Tight, worn, or burnt motor 5. Replace motor.
RUNNINGbearings.
6. Open rotor windings. 6. Replace motor.
7. Worn motor brushes. 7. Replace motor.
8. Shaft binding-blade misaligned. 8. Check alignment. Repair or replace
as necessary.
9. Defective resistors 9. Rectify or replace.
1. Incorrect voltage. 1. Check voltage.
2. Open or defective fuse or relay. 2. Check and replace as necessary.
B.3. Defective thermostat control or 3. Replace thermostat or
COMPRESSORpressure switch. pressure switch.
CLUTCH4. Shorted or open field coil. 4. Replace coil.
INOPERATIVE5. Bearing seized (clutch will not 5. Replace clutch pulley assembly.
disengage).
6. Refrigeration circuit problem causing
heavy load and excessive drive
torque.6. Check and rectify.
1. Incorrect alignment. 1. Check alignment; repair as
necessary.
2. Loose belt. 2. Adjust to proper tension.
C.3. Compressor not mounted securely. 3. Repair as necessary.
COMPRESSOR4. Bearing in clutch-pulley 4. Remove clutch and replace
CLUTCHassembly not pressed in. clutch pulley assembly.
NOISY5. Low voltage to clutch. 5. Check connections and voltage.
6. Clutch will not spin freely. 6. Refer to B5 above.
7. Oil on clutch face. 7. Check compressor seals for leaks.
8. Slipping clutch. 8. Refer to C5 above. Then check air
gap.
9. Overloaded or locked compressor. 9. Repair or replace compressor.
10. Icing. 10. Check for suction line frosting.
Replace expansion valve if
necessary.
Replace receiver/drier if necessary.
D.1. Motor and/or blades improperly 1. Check mountings, adjust as
CONDENSERmounted. necessary.
VIBRATION2. Foreign matter build-up on 2. Clean blades with a suitable
blades. non-inflammable cleaner.
3. Excessive wear of motor bearings. 3. Replace motor.

82AIR CONDITIONING
2
FAULT DIAGNOSIS REFRIGERATION SYSTEM FAULTS
For any refrigeration system to function properly all
components must be in good working order. The unit
cooling cycle and the relationship between air
discharge temperature and ambient temperature and
the pressures at the compressor can help to
determine proper operation of the system.
The length of any cooling cycle is determined by such
factors as ambient temperature and humidity,
thermostat setting, compressor speed and air leakage
into the cooled area, etc. With these factors constant,
any sudden increase in the length of the cooling cycle
would be indicative of abnormal operation of the air
conditioner.
The low and high side pressures at the compressor
will vary with changing ambient temperature, humidity,
in-car temperature and altitude.
The following items should be checked before
operating the system:
1.Compressor drive belt tension.
2.Compressor magnetic clutch operation.
3.Condenser fan operation.
4.Condenser fins, dirt will cause poor cooling and
higher operating temperatures.The following conditions should be checked after
operating the system for several minutes:
1.All high pressure lines and components should
be hot to the touch.
2.All low pressure lines should be cool to the
touch.
3.Inlet and outlet temperatures at the receiver/drier
should be at the same temperature (warm). Any
very noticeable temperature difference indicates
a blocked receiver/drier.
4.Heavy frost on the inlet to the expansion valve
may indicate a defective valve or moisture in the
system.
5.Evaporation air temperature will vary with
ambient temperature and humidity. As humidity
increases the outlet temperature will be higher.

82AIR CONDITIONING
4
FAULT DIAGNOSISFAULT CAUSE REMEDY
E.
NOISY
EXPANSION
VALVE
(steady hissing)1. Low refrigerant charge; evident by
bubbles in sight glass.1. Leak test. Repair or replace
components as required.
F.1. Expansion valve not operating 1. Refer to C-2, C-3, D-1
INSUFFICIENTproperly. and E.
COOLING2. Low refrigerant charge-evident 2. Refer to B-1 and E.
by bubbles in sight glass.
3. Compressor not pumping. 3. Refer to B-2 and B-3
G.1. Belt tension. 1. Adjust belt tension.
COMPRESSOR2. Excessive head pressure. 2. Refer to A-1 through
BELTA-4 and C-6.
SLIPPING3. Incorrect alignment of pulleys 3. Repair as needed.
or worn belt not riding properly.
4. Nicked or broken pulley. 4. Replace as needed.
5. Seized compressor. 5. Replace compressor.
1. Loose or missing mounting bolts. 1. Repair as necessary.
2. Broken mounting bracket. 2. Replace bracket.
3. Loose flywheel or clutch 3. Repair as necessary.
retaining bolt.
H.4. Rough idler pulley bearing. 4. Replace bearing.
ENGINE5. Bent, loose, or improperly 5. Repair as necessary.
NOISEmounted engine drive pulley.
AND/OR6. Defective compressor bearing. 6. Replace bearing.
VIBRATION7. Insecure mountings of 7. Repair as necessary.
accessories; generator, power
steering, air filter, etc.
8. Excessive head pressure. 8. Refer to A-1, A-2, A-3
A-4 and C-6.
9. Incorrect compressor oil level. 9. Refer to compressor Oil
Level Check.
HEATER AND AIR CONDITIONING - CIRCUIT
DIAGRAMS
1.For details of heating and air conditioning
electrics
See Electrical Trouble Shooting
Manual.

82AIR CONDITIONING
2
ADJUSTMENT SERVICING PRECAUTIONS
Care must be taken when handling refrigeration
system components. Units must not be lifted by their
hoses, pipes or capillary lines. Hoses and lines must
not be subjected to any twist or stress. Ensure that
hoses are positioned in their correct run before fully
tightening the couplings, and ensure that all clips and
supports are used. Torque wrenches of the correct
type must be used when tightening refrigerant
connections to the stated value. An additional wrench
must be used to hold the union to prevent twisting of
the pipe.
Before connecting any hose or pipe ensure that
refrigerant oil is applied to the seat of the new '0' ring
but not to the threads.
Check the oil trap for the amount of oil lost.
All protective plugs on components must be left in
place until immediately prior to connection.
The receiver/drier contains desiccant which absorbs
moisture. It must be positively sealed at all times.
CAUTION: Whenever the refrigerant
system is opened, the receiver/drier must
be renewed immediately before evacuating
and recharging the system.
Use alcohol and a clean cloth to clean dirty
connections.
Ensure that all new parts fitted are marked for use
withR134a.
Refrigerant oil
Use the approved refrigerant lubricating oil:
Nippon Denso ND-OIL 8
Unipart R134a ND-OIL8
CAUTION: Do not use any other type of
refrigerant oil.
Refrigerant oil easily absorbs water and must not be
stored for long periods. Do not pour unused oil back
into the container.
When renewing system components, add the
following quantities of refrigerant oil:
Condenser 40ml..........................................................
Evaporator 80ml..........................................................
Pipe or hose 20ml........................................................
Receiver/drier 20ml......................................................
Total of refrigerant oil in system = 180ml = 6.3 Fl
ozA new compressor is sealed and pressurised with
Nitrogen gas, slowly release the sealing cap, gas
pressure should be heard to release as the seal is
broken.
NOTE: A new compressor should always
have its sealing caps in place and must
not be removed until immediately prior to
fitting
Fitting a new compressor
A new compressor is supplied with an oil fill (X) of:
180ml
A calculated quantity of oil must be drained from a
new compressor before fitting.
To calculate the quantity of oil to be drained:
1.Remove sealing plugs from the OLD compressor
2.Invert compressor and gravity drain oil into
measuring cylinder. Rotating the compressor
clutch plate will assist complete draining.
3.Note the quantity of oil drained (Y).
4.Calculate the quantity (Q) of oil to be drained
from the NEW compressor using the following
formula:
X - (Y + 20ml) = Q
Rapid refrigerant discharge
When the air conditioning system is involved in
accident damage and the circuit is punctured, the
refrigerant is discharged rapidly. The rapid discharged
of refrigerant will also result in the loss of most of the
oil from the system. The compressor must be
removed and all the remaining oil in the compressor
drained and refilled as follows:
1.Gravity drain all the oil, assist by rotating the
clutch plate (not the pulley).
2.Refill the compressor with the following amount
of new refrigerant oil:
130ml
3.Plug the inlet and outlet ports.

82AIR CONDITIONING
4
ADJUSTMENT Evacuation and recharging
1.Add refrigerant oil to compressor if necessary.
2.Renew the receiver/drier.
CAUTION: When a major repair has been
carried out, a leak test should be carried
out using inert gas.
3.Connect a Refrigerant Station to the high and
low pressure servicing connections.
CAUTION: Whenever the refrigerant
system is opened, the receiver/drier must
be renewed immediately before evacuating
and recharging the system.
4.Operate the refrigerant evacuation system
according to the manufacturer's instructions.
NOTE: If the vacuum reading is below
700mmHg after 15 minutes, suspect a leak
in the system. Partially recharge the
system and check for leaks using an electronic
leak tester. Check suction lines first, then run the
compressor for 5 minutes and then check the high
pressure lines.
CAUTION: The system must be evacuated
immediately before recharging
commences. Delay between evacuation
and recharging is not permitted.
5.Operate the refrigerant recharging system
according to the manufacturer's instructions:-
Refrigerant required to charge system:
Without rear air conditioning = 0.90kg (32 fl/oz)
With rear air conditioning = 1.15kg (40 fl/oz)
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
car 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
are 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.

82AIR CONDITIONING
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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. Check the sight glass for bubbles or
foam. The sight glass should be generally clear
after five minutes running, occasional bubbles
being acceptable. Continuous bubbles may
appear in a serviceable system on a cool day, or
if there is insufficient air flow over the condenser
at a high ambient temperature.
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.
COMPRESSOR DRIVE BELT
Service repair no - 82.10.01.
Tdi -
See ENGINE, Repair, Compressor drive belt
V8i and MpiSee ENGINE, Repair, Drive belt

AIR CONDITIONING
5
REPAIR COMPRESSOR
Service repair no - 82.10.20
Remove
1.Disconnect battery negative lead.
2.Recover refrigerant from air conditioning system.
See Adjustment, Refrigerant Recovery
Recycling Recharging
3.Remove screws retaining centre panel to fan
cowl
4.Remove centre panel.
V8i engine illustrated
5.Remove 2 bolts securing hose flanges to
compressor.
WARNING: Wear eye and hand protection
when disconnecting components
containing refrigerant. Plug all exposed
connections immediately.6.Disconnect high pressure hose from
compressor.
7.Disconnect low pressure hose from compressor.
8.Remove 'O' ring from each flange.
9.Disconnect electrical lead from compressor
clutch.
10.Release drive belt from compressor pulley.
See
ENGINE, Repair, Drive Belt
11.Remove 4 bolts securing compressor to
mounting bracket.
12.Remove compressor from mounting bracket.
Refit
13.New compressor to be fitted: Drain oil from new
compressor outlet port. Drain and measure oil
from old compressor. Measure new oil equal to
amount drained from old compressor, add 30 ml
extra to this amount and refill new compressor
through outlet port.
14.Locate compressor in mounting bracket, fit bolts.
Tighten to
25 Nm.
15.Connect electrical lead to compressor clutch.
16.Fit new 'O' rings to high and low pressure hose
flanges, lubricate with refrigerant oil.
17.Engage hose flanges, fit bolts. Tighten to
10
Nm.
18.Fit compressor drive belt.See ENGINE, Repair,
Drive Belt
19.Fit centre panel to fan cowl.
20.Evacuate and recharge air conditioning system.
See Adjustment, Refrigerant Recovery
Recycling Recharging
21.Perform a leak test on disturbed joints.
22.Carry out a functional check.