Isuzu N-Series. Manual - part 67

1B-38 AIR CONDITIONING

Removal

Preparation:
Disconnect the battery ground cable.
Discharge and recover refrigerant.

1. Front grille
2. Clamp / Clip (Except 4HK1-TC Engine Model For

Australia)

3. Band clip (4HK1-TC Engine Model For Australia)
4. Refrigerant line (Compressor — Condenser)
5. Refrigerant line (Compressor — Evaporator)
6. Refrigerant line (Receiver / Drier — Evaporator)

• Use a back-up wrench when disconnecting and re-

connecting the refrigerant lines.

• When removing the refrigerant line connecting

part, the connecting part should immediately be
plugged or capped to prevent foreign matter from
being mixed into the line.

Installation

To install, follow the removal steps in the reverse order,
noting the following points:

1. O-rings cannot be reused. Always replace new

ones.

2. Be sure to apply new specified compressor oil to

the O-rings when connecting refrigerant lines.

3. If installing a new refrigerant line, be sure to add 10

cc (0.3 lmp fl oz) of new specified compressor oil to
a new one.

4. Tighten the refrigerant line to the specified torque.

(Refer to “SERVICE INFORMATION” for FIXING
TORQUE in section 00.)

COMPRESSOR OVERHAUL EXCEPT TAIWAN 1D1-1

HEATING AND AIR CONDITIONING

SECTION 1D1

COMPRESSOR OVERHAUL EXCEPT TAIWAN

Caution:

When fasteners are removed, always reinstall them at the same location from which they were removed. If a fastener
needs to be replaced, use the correct part number fastener for that application. If the correct part number fastener is
not available, a fastener of equal size and strength (or stronger) may be used.

Fasteners that are not reused, and those requiring thread locking compound, will be called out. The correct torque
values must be used when installing fasteners that require it. If the above conditions are not followed, parts or system
damage could result.

Contents

GENERAL DESCRIPTION .................................1D1-2
GENERAL INFORMATION.................................1D1-3

Compressor Oil................................................1D1-3

SERVICE PROCEDURES ..................................1D1-5

Compressor Overhaul .....................................1D1-5

1D1-2 COMPRESSOR OVERHAUL EXCEPT TAIWAN

GENERAL DESCRIPTION

When servicing the compressor, keep dirt or foreign ma-
terial from getting on or into the compressor parts and
system. Clean tools and a clean work area are important
for proper service. The compressor connections and the
outside of the compressor should be cleaned before any
“On-Vehicle” repair, or before removal of the compres-
sor. The parts must be kept clean at all times and any
parts to be reassembled should be cleaned with Trichlo-
roethane, naphtha, kerosene, or equivalent solvent, and
dried with dry air. Use only lint free cloths to wipe parts.
The operations described below are based on bench
overhaul with compressor removed from the car, except
as noted. They have been prepared in order of accessi-
bility of the components. When the compressor is re-
moved from the car for servicing, the oil remaining in the
compressor should be discarded and new refrigerant oil
added to the compressor.
Magnetic clutch assembly repair procedures require
that the system be discharged of refrigerant. (Refer to
Section 1B for “REFRIGERANT RECOVERY”.)
Compressor malfunction will appear in one of four ways:
noise, seizure, leakage or low discharge pressure. Res-
onant compressor noises are not cause for alarm; how-
ever, irregular noise or rattles may indicate broken parts
or excessive clearances due to wear. To check seizure,
de-energize the magnetic clutch and check to see if the
drive plate can be rotated. If rotation is impossible, the
compressor is seized. Low discharge pressure may be
due to a faulty internal seal of the compressor, or a re-
striction in the compressor. Low discharge pressure
may also be due to an insufficient refrigerant charge or
a restriction elsewhere in the system. These possibilities
should be checked prior to servicing the compressor. If
the compressor is inoperative, but is not seized, check
to see if current is being supplied to the magnetic clutch
coil terminals.
This vehicle is provided with a swash plate type com-
pressor.

Swash plate compressors have a swash (slanted) plate
mounted on the shaft. When the shaft turns, the rotation
of the swash plate is converted to reciprocating piston
motion which sucks in and compresses the refrigerant
gas.
Shaft seal (Lip type) is installed between the valve plate
and shaft a cylinder head to prevent refrigerant gas
leaks. A specified amount of compressor oil is contained
in the oil pan.
This oil is supplied to the cylinders, bearings, etc., by an
oil pump which is connected to the swash plate shaft.
With some compressors the differential between the in-
take pressure and discharge pressure generated while
the compressor is operating is used for lubrication in-
stead of an oil pump. 
Three pistons are arranged at 120 degree intervals
around the center of the swash plate shaft. These pis-
tons are connected to the ends of the swash plate
through balls.
The rotation of the swash plate causes reciprocating
movement of the piston inside the cylinders, with each
piston operating as two cylinders. Because of that, the
compressor operates as though it has 6 cylinders.
The specified amount of the compressors oil is 180 cc
(5.0 Imp fl oz).
The oil used in the R-134a system compressor differs
from that used in R-12 systems.
Also, compressor oil to be used varies according to the
compressor model. Be sure to avoid mixing two or more
different types of oil.
If the wrong oil is used, lubrication will be poor and the
compressor will seize or malfunction.
(Refer to Section 1B “ON-VEHICLE SERVICE” for Pre-
cautions for R-134a Air Conditioning System in this
manual.)

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COMPRESSOR OVERHAUL EXCEPT TAIWAN 1D1-3

GENERAL INFORMATION

Compressor Oil

Oil specification

• 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.

Specified Compressor Oil
ZXL-100PG (ISUZU PART NO. 8-97101-338-0)

Handling of oil

• The oil should be free from moisture, dust, metal

powder, etc.

• Do not mix with other oil.
• The water content in the oil increases when ex-

posed to the air. After use, seal oil from air imme-
diately. 
(R-134a PAG Compressor Oil absorbs moisture
very easily than R-12.)

• The compressor oil must be stored in steel contain-

ers, not in plastic containers.

Compressor oil check

The oil used to lubricate the compressor is circulating
with the refrigerant.
Whenever replacing any component of the system or a
large amount of gas leakage occurs, add oil to maintain
the original amount of oil.
Oil Capacity

Checking and Adjusting for Used Compressor

1. Perform Oil return operation. 

(Refer to “Oil Return Operation” in this section.) 

2. Discharge refrigerant and remove the compressor.
3. Drain the compressor oil and measure the extract-

ed oil with a measuring cylinder.

4. If the amount of oil drained is much less than 90 cc

(2.5 Imp fl oz), some refrigerant may have leaked
out. Conduct leak tests on connections of each
system, and if necessary, repair or replace faulty
parts.

5. Check the compressor oil for contamination. 

(Refer to “Contamination of Compressor Oil” in this
section.)

6. Adjust oil level following the procedure below.

7. Install the compressor, then evacuate, charge and

perform oil return operation.

8. Check system operation.

When it is impossible to perform oil return
operation, the compressor oil should be checked in
the following order:

1. Discharge refrigerant and remove the compressor.
2. Drain the compressor oil and measure the extract-

ed oil with a measuring cylinder.

3. Check the oil for contamination.
4. If more than 120 cc (3.4 lmp fl oz) of oil is extracted

from the compressor, supply same amount of oil to
the compressor to be installed. 
If the amount of oil extracted is less than 120 cc
(3.4 lmp fl oz), recheck the compressor oil in the
following order:

5. Supply 120 cc (3.4 lmp fl oz) of oil to the compres-

sor and install it on to the vehicle.

6. Perform oil return operation. 

Capacity total in system

180 cc (5.0 Imp fl oz)

Compressor (Service
parts) charging amount

180 cc (5.0 Imp fl oz)

Collected Amount

Charging Amount

more than 120 cc

(3.4 Imp fl oz)

same as collected amount

less than 120 cc

(3.4 lmp fl oz)

120 cc (3.4 lmp fl oz)

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