Isuzu Trooper (2000 year). Service manual - part 20

HEATING, VENTILATION AND AIR CONDITIONING (HVAC) 1A–49

CAUTION: Compressor (PAG) oil to be used varies
according to the compressor model. Be sure to apply
oil specified for the model of compressor.

850RW002

O-rings (2) must be closely aligned with the raised portion
(1) of refrigerant line.

850RW003

Insert the nut into the union.
First, tighten the nut by hand as much as possible, then
tighten the nut to the specified torque.

850RW004

1A–50 HEATING, VENTILATION AND AIR CONDITIONING (HVAC)

Leak Check

Inspection of refrigerant leak
Refrigerant leak may cause an adverse effect not only on
the performance and durability of each component of the
air-conditioner, but also on the global atmosphere.

Therefore, it is most important to repair refrigerant leak
when there is any leak found.

Inspection flow of refrigerant leak 

Step

Action

Yes

No

1

1. Evacuate the refrigerant system.
2. Charge the refrigerant.

Is there any refrigerant leak?

Repair refrigerant

system

Go To Step 2

2

1. Operate the compressor for more than 5 minutes to raise the

pressure on the high pressure side.

Is there any refrigerant leak at high pressure components?

Repair refrigerant

system

Compressor

operation to be

confirmed

Inspection steps
Check the components of the air conditioner to see if
there occurs any refrigerant leak along the flow of
refrigerant.

NOTE:

D

To avoid an error in the detection of refrigerant leak,
make sure there is no refrigerant vapor or cigarette
smoke around the vehicle before conducting the
inspection.
Also, select a location where the refrigerant vapor will
not be blown off by wind.

D

Inspection should be conducted chiefly on the pipe
connections and sections where a marked oil
contamination is found.
When refrigerant is leaking, oil inside is also leaking at
the same time.

D

It is not possible to visually check the leak from inside
the cooling unit. Follow the method below when
checking.
Remove the drain hose or resistor of the cooling unit,
and insert a leak detector to see if there occurs any
leak.

High pressure side

1. Discharger section of compressor
2. Inlet/outlet section of condenser
3. Inlet/outlet section of receiver driver
4. Inlet section of cooling unit

Low pressure side

1. Outlet section of cooling unit
2. Intake section of compressor

Major checking points of refrigerant leak

Compressor

D

Pipe connection

D

Sealing section of shaft

D

Mating section of cylinder

Condenser

D

Pipe connection

D

Welds of condenser body

Receiver drier

D

Pipe connection

D

Attaching section of pressure switch

D

Section around the sight glass

Evaporator unit (cooling unit)

D

Pipe connection

D

Connections of expansion valve

D

Brazed sections of evaporator

NOTE:

D

The evaporator and expansion valve are contained in
the case. Remove the drain hose or the resistor of the
cooling unit and insert a leak detector when checking
for any leak.

Flexible hose

D

Pipe connection

D

Caulking section of the hose

D

Hose (cracks, pinholes, flaws)

Pipe

D

Pipe connection

D

Pipe (cracks, flaws)

Charge Valve

NOTE:

D

The charge valve, which is used to connect the gauge
manifold, is normally provided with a resin cap. When
the valve inside gets deteriorated, refrigerant will leak
out.

Leak at Refrigerant Line Connections

1. Check the torque on the refrigerant line fitting and, if

too loose, tighten to the specified torque.

D

Use two wrenches to prevent twisting and damage
to the line.

D

Do not over tighten.

2. Perform a leak test on the refrigerant line fitting.

HEATING, VENTILATION AND AIR CONDITIONING (HVAC) 1A–51

3. If the leak is still present, discharge and recover the

refrigerant from the system.

4. Replace the O-rings.

D

O-rings cannot be reused. Always replace with new
ones.

D

Be sure to apply the specified compressor oil to the
new O-rings.

5. Retighten the refrigerant line fitting to the specified

torque.

D

Use two wrenches to prevent twisting and damage
to the line.

6. Evacuate, charge and retest the system.

Leaks In The Hose

If the compressor inlet or outlet hose is leaking, the entire
hose must be replaced.  The refrigerant hose must not be
cut or spliced for repair.

1. Locate the leak.
2. Discharge and recover the refrigerant.
3. Remove the hose assembly.

D

Cap the open connections at once.

4. Connect the new hose assembly.

D

Use two wrenches to prevent twisting or damage to
the hose fitting.

D

Tighten the hose fitting to the specified torque.

5. Evacuate, charge and test the system.

Compressor Leaks

If leaks are located around the compressor shaft seal or
shell, replace or repair the compressor.

Recovery, Recycling, Evacuation and
Charging of HFC-134a

Air conditioning systems contain HFC-134a. This is a
chemical mixture which requires special handling
procedures to avoid personal injury.

D

Always wear safety goggles and protective gloves.

D

Always work in a well-ventilated area. Do not weld or
steam clean on or near any vehicle-installed air
conditioning lines or components.

D

If HFC-134a should come in contact with any part of
the body, flush the exposed area with cold water and
immediately seek medical help.

D

If it is necessary to transport or carry any container of
HFC-134a in a vehicle, do not carry it in the
passenger compartment.

D

If it is necessary to fill a small HFC-134a container
from a large one,never fill the container completely.
Space should always be allowed above the liquid for
expansion.

D

HFC-134a and R-12 should never be mixed as their
compositions are not the same.

D

HFC-134a PAG oil tends to absorb moisture more
quickly than R-12 mineral oil and, therefore, should
be handled more carefully.

D

Keep HFC-134a containers stored below 40

°

C

(100

°

F).

WARNING:

D

SHOULD HFC-134A CONTACT YOUR EYE(S),
CONSULT A DOCTOR IMMEDIATELY.

D

DO NOT RUB THE AFFECTED EYE(S). INSTEAD,
SPLASH QUANTITIES OF FRESH COLD WATER
OVER THE AFFECTED AREA TO GRADUALLY
RAISE THE TEMPERATURE OF THE
REFRIGERANT ABOVE THE FREEZING POINT.

D

OBTAIN PROPER MEDICAL TREATMENT AS
SOON AS POSSIBLE. SHOULD THE HFC-134A
TOUCH THE SKIN, THE INJURY MUST BE
TREATED THE SAME AS SKIN WHICH HAS BEEN
FROSTBITTEN OR FROZEN.

Refrigerant Recovery

The refrigerant must be discharged and recovered by
using the J-39500 (ACR

4

:HFC-134a Refrigerant

Recovery/Recycling/Recharging/System) or equivalent
before removing or mounting air conditioning parts.

1. Connect the high and low charging hoses of the

ACR

4

(or equivalent) as shown below.

901RS141

Legend

(1) Low Side
(2) High Side

2. Recover the refrigerant by following the

Manufacturer’s Instructions.

3. When a part is removed, put a cap or a plug on the

connecting portion so that dust, dirt or moisture
cannot get into it.

1A–52 HEATING, VENTILATION AND AIR CONDITIONING (HVAC)

Refrigerant Recycling

Recycle the refrigerant recovered by J-39500
(ACR

4

:HFC-134a Refrigerant Recovery / Recycling /

Recharging / System) or equivalent.
For the details of the actual operation, follow the steps in
the ACR

4

(or equivalent) Manufacturer’s Instructions.

Evacuation of The Refrigerant System

901RS142

Legend

(1) Low Side
(2) High Side

NOTE: Explained below is a method using a vacuum
pump. Refer to the ACR

4

(or equivalent) manufacturer’s

instructions when evacuating the system with a ACR

4

(or

equivalent).
Air and moisture in the refrigerant will cause problems in
the air conditioning system.  Therefore, before charging
the refrigerant, be sure to evacuate air and moisture thor-
oughly from the system.

1. Connect the gauge manifold.

D

High-pressure valve (HI) — Discharge-side.

D

Low-pressure valve (LOW) — Suction-side.

2. Discharge and recover the refrigerant.
3. Connect the center hose of the gauge manifold set to

the vacuum pump inlet.

4. Operate the vacuum pump, open shutoff valve and

then open both hand valves.

5. When the low-pressure gauge indicates

approximately 750 mmHg (30 inHg), continue the
evacuation for 5 minutes or more.

6. Close both hand valves and stop the vacuum pump.
7. Check to ensure that the pressure does not change

after 10 minutes or more.

D

If the pressure changes, check the system for
leaks.

D

If leaks occur, retighten the refrigerant line
connections and repeat the evacuation steps.

8. If no leaks are found, again operate the vacuum pump

for 20 minutes or more.  After confirming that the
gauge manifold pressure is at 750 mmHg (30 inHg),
close both hand valves.

9. Close positive shutoff valve. Stop the vacuum pump

and disconnect the center hose from the vacuum
pump.

Charging The Refrigerant System

There are various methods of charging refrigerant into the
air conditioning system.
These include using J-39500 (ACR

4

:HFC-134a

Refrigerant Recovery/Recycling/Recharging/System) or
equivalent and direct charging with a weight scale
charging station.

Charging Procedure

D

ACR

4

(or equivalent) Method

For the charging of refrigerant recovered by ACR

4

(or

equivalent), follow the manufacturer’s instruction.

901RS141

Legend

(1) Low Side
(2) High Side

D

Direct charging with a weight scale charging
station method

1. Make sure the evacuation process is correctly

completed.

2. Connect the center hose of the manifold gauge to the

weight scale.