Isuzu N-Series. Manual - part 60

1B-10 AIR CONDITIONING

ON-VEHICLE SERVICE

Precautions for Refrigerant -134a (R-134a)
Air Conditioning System

This vehicle is equipped with Refrigerant-134a (R-134a)
air conditioning system.
R-134a and R-12 systems require different types of lu-
bricating oil. Components designed solely for use with
one refrigerant and oil type must never be interchanged
with components designed solely for use with another
refrigerant and oil type.
R-134a Refrigerant:

• R-134a differs entirely from R-12 in its composition

and, therefore, the two should never be mixed. Al-
ways charge the specified amount of R-134a.

• The pressure characteristics of R-134a differ from

those of R-12. The low pressure is lower, and the
high pressure is higher.

R-134a Compressor oil:

• The R-134a system requires a synthetic (PAG)

compressor oil whereas the R-12 system requires
a mineral compressor oil. The two oils must never
be mixed.

• Compressor (PAG) oil varies according to com-

pressor model. Be sure to use oil specified for the
model of compressor.

Oil Specification
ZXL-100PG (ISUZU PART No. 8-97101-338-0)

• The PAG compressor oil for the R-134a system

tends to absorb moisture more quickly than mineral
oil. When air conditioning parts are removed for
servicing, all the open ends of parts and compo-
nents must be sealed with caps to keep out con-
taminants.

• The PAG compressor oil must be stored in metal

containers, not in plastic containers.

Service charge valve:

• The diameter of the service charge valve for the R-

134a system is made larger than that for the R-12
system to prevent cross-contamination. In addi-
tion, the screw-in type joint of the R-12 system is
replaced with a quick joint type in the R-134a sys-
tem.

• To prevent refrigerant from escaping during instal-

lation and removal of charging hoses from the ser-
vice charge valves, quick-joint type fittings are
used.
Connection: Push on firmly until locked (a “click”
will be heard).
Removal: Hold the grip-ring and pull to remove.

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Legend

1. Refrigerant line
2. Cap
3. Evaporator

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AIR CONDITIONING 1B-11

• Air conditioning manifold gauges, charging hoses and other service tools designed exclusively for the R-134a

system must be used with this vehicle.

Legend

1. Manifold gauge

5. Charge valve handle

2. Quick joint (Low side)

6. Vacuum pump

3. Charging hose

7. Service container

4. Quick joint (High side)

N1A0059E

1B-12 AIR CONDITIONING

• Do not use the same vacuum pump for evacuating

the R-134a and R-12 systems interchangeably
(The vacuum pump hose fitting is a M10X1.5).

• R-134a vacuum pumps must have a positive shut-

off valve.

Caution:

Never use the same vacuum pump for both R-134a and
R-12 systems, as cross contamination of compressor oil
may occur.

Refrigerant Recovery, Recycling and Charging

• Avoid releasing the R-134a into the atmosphere.

Use the ACR

(R-134a Refrigerant Recovery/ Re-

cycling/ Recharging/ System) or equivalent to re-
cover and recycle R-134a. Note that the ACR

(or

equivalent) is not interchangeable between the R
134a and R-12 systems.
ACR

(115V 60Hz): 5-8840-0629-0 (J-39500-A)

ACR

(220-240V 50/60Hz): 5-8840-0630-0 (J-

39500-220A)
ACR

(220-240V 50/60Hz Australian model): 5-

8840-0631-0 (J-39500-220ANZ)

Refrigerant Leak Inspection

• The flame type gas leak detector for the R-12 sys-

tem cannot be used with the R-134a system.

• The electric leak detector for the R-12 cannot be

used with the R-134a system as the R-134a parti-
cles are far smaller than the R-12 molecules and,
therefore, may not be always detected. Use leak
detectors designed exclusively for the R-134a sys-
tem.

Precautions for Replacement or Repair of
R-134a Air Conditioning Parts

There are certain procedure, practices and precautions
that should be followed when servicing air conditioning
systems:

• Keep your work area clean.
• Always wear safety goggle and protective gloves

when working on refrigerant systems.

• Beware of the danger of carbon monoxide fumes

caused by running the engine.

• Beware of discharged refrigerant in enclosed or im-

properly ventilated garages.

• Always disconnect the negative battery cable and

discharge and recover the refrigerant whenever re-
pairing the air conditioning system.

• When discharging and recovering the refrigerant,

do not allow refrigerant to discharge too fast; it will
draw compressor oil out of the system.

• Keep moisture and contaminants out of the sys-

tem. When disconnecting or removing any lines or
parts, use plugs or caps to close the fittings imme-
diately.
Never remove the caps or plugs until the lines or
parts are reconnected or installed.

• When disconnecting or reconnecting the lines, use

two wrenches to support the line fitting, to prevent
from twisting or other damage.

Legend

1. M10

× 1.5 (Hose fitting)

N1A0060E

N1A0061E

AIR CONDITIONING 1B-13

• Always install new O-rings whenever a connection

is disassembled.

• Before connecting any hoses or lines, apply new

specified compressor oil to the O-rings.

• When removing and replacing any parts which re-

quire discharging the refrigerant circuit, the opera-
tions described in this Section must be performed
in the following sequence:

1. Using the ACR

(R-134a Refrigerant Recovery/

Recycling/ Recharging/ System) or equivalent to
thoroughly discharge and recover the refrigerant.
ACR

(115V 60Hz): 5-8840-0629-0 (J-39500-A)

ACR

(220-240V 50/60Hz): 5-8840-0630-0 (J-

39500-220A)
ACR

(220-240V 50/60Hz Australian model): 5-

8840-06311-0 (J-39500-220ANZ)

2. Remove and replace the defective part.
3. After evacuation, charge the air conditioning sys-

tem and check for leaks.

Repair of Refrigerant Leaks

Refrigerant Line Connections
Install new O-rings, if required. When disconnecting or
connecting lines, use two wrenches to prevent the con-
necting portion from twisting or becoming damaged.

When connecting the refrigerant line at the block joint,
securely insert the projecting portion of the joint portion
into the connecting hole on the unit side and secure with
a bolt.

Apply specified compressor oil to the O-rings prior to
connecting.

Caution:

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

N1A0061E

Legend

1. O-ring
2. Block joint

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