Defender 300Tdi (1996+). Manual - part 93

AIR CONDITIONING

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 spanner
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
with R134a.

Refrigerant oil

Use the approved refrigerant lubricating oil - Nippon
Denso ND-OIL 8.

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 quantity of refrigerant oil in system = 140ml

A 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 these
must not be removed until immediately

prior to fitting

A new compressor is supplied with an oil fill of 140ml.

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 (Yml).
4. Calculate the quantity (Qml) of oil to be drained

from the NEW compressor using the following
formula:

Xml - (Yml + 20ml) = Qml

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 discharge
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 90ml of new

refrigerant oil.

3. Plug the inlet and outlet ports.

Servicing Equipment

The following equipment is required for full servicing
of the air conditioning system.

Recovery, recycling and charging station
Leak detector
Thermometer +20

C to -60

Safety goggles and gloves

AIR CONDITIONING

ADJUSTMENT

REFRIGERANT RECOVERY, RECYCLING,
RECHARGING

WARNING: The air conditioning system is
charged with a high pressure, potentially
toxic refrigerant. Repairs or servicing must

only be carried out by an operator familiar with
both the vehicle system and the charging and
testing equipment.

All operations must be carried out in a
well-ventilated area away from open flame and
heat sources.
Always wear safety goggles and gloves when
opening refrigerant connections.

WARNING: Wear eye and hand safety
protection. Open connections slowly in
case liquid or pressure is present. Allow to

bleed off slowly.

CAUTION: Overcharging air conditioning
system will cause excessive head
pressure.

An air conditioning portable Refrigerant Recovery
Recycling Recharging Station for use with R134a
refrigerant incorporates all the features necessary to
recover refrigerant R134a from the air conditioning
system, to filter and remove moisture, to evacuate and
recharge with the reclaimed refrigerant. The unit can
also be used for performance testing and air
conditioning system analysis.

The operator must adhere to the equipment
manufacturers’ instructions.

Recovery and recycling

1. Connect a Refrigerant Station to the high and

low pressure servicing connections.

2. Operate the refrigerant recovery system

according to the manufacturers instructions.

3. Measure the amount of oil discharged from the

system. Add an equal amount of new refrigerant
oil to compressor before evacuation sequence.

WARNING: Refrigerant must always be
recycled before reuse, to ensure that the
purity of the refrigerant is high enough for

safe use in the air conditioning system. Recycling
should always be carried out with equipment
which is design certified by Underwriter
Laboratory Inc. for compliance with SAE-J1991.
Other equipment may not recycle refrigerant to
the required level of purity.

A R134a Refrigerant Recovery Recycling
Recharging Station must not be used with any
other type of refrigerant.

Refrigerant R134a from domestic and commercial
sources must not be used in motor vehicle air
conditioning systems.

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 manufactures 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.

AIR CONDITIONING

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

ADJUSTMENT

AIR CONDITIONING SYSTEM - PERFORMANCE
TEST

WARNING: R134a is hazardous

See

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

4 - 10

18 - 28 lbf/in

213 - 299 lbf/in

1.2 - 1.9 bar

14.7 - 20.6 bar

25 - 29

9 - 19

27 - 37 lbf/in

256 - 341 lbf/in

1.9 - 2.6 bar

17.6 - 23.5 bar

30 - 35

20 - 27

33 - 47 lbf/in

299 - 384 lbf/in

2.3 - 3.2 bar

20.6 - 26.5 bar

Table 1

Ambient

Compound Gauge

High Pressure

Temperature

Readings

Gauge Readings

bar

lbf/in

bar

lbf/in

1,03-1,4

15-20

6,9-10,3

100-150

26,7

1,4-1,72

20-25

9,6-13,1

140-190

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

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