Contamination Of Compressor Oil; Oil Return Operation; Replacement Of Component Parts; Compressor Leak Testing (External And Internal) - Isuzu 2000 Trooper Workshop Manual

1. Perform oil return operation.
2. Discharge and recover the refrigerant and remove the
compressor.
3. Drain the compressor oil and measure the extracted
oil.
4. Check the compressor oil for contamination.
5. Adjust the oil level as required.
(Amount of oil drained
from used compressor)
more than 90 cc (3.0
fl.oz)
less than 90 cc (3.0 fl.oz)
6. Evacuate, charge and perform the oil return
operation.
7. Check the system operation.

Contamination of Compressor Oil

Unlike engine oil, no cleaning agent is added to the
compressor oil. Even if the compressor runs for a long
period of time (approximately one season), the oil never
becomes contaminated as long as there is nothing wrong
with the compressor or its method of use.
Inspect the extracted oil for any of the following
conditions:
D The capacity of the oil has increased.
D The oil has changed to red.
D Foreign substances, metal powder, etc., are present
in the oil.
If any of these conditions exists, the compressor oil
is contaminated.
compressor oil is discovered, the receiver/drier must
be replaced.

Oil Return Operation

There is close affinity between the oil and the refrigerant.
During normal operation, part of the oil recirculates with
the refrigerant in the system. When checking the amount
of oil in the system, or replacing any component of the
system, the compressor must be run in advance for oil
return operation. The procedure is as follows:
1. Open all the doors and the engine hood.
2. Start the engine and air conditioning switch to "ON"
and set the fan control knob at its highest position.
3. Run the compressor for more than 20 minutes
between 800 and 1,000 rpm in order to operate the
system.
4. Stop the engine.

Replacement of Component Parts

When replacing the system component parts, supply the
following amount of oil to the component parts to be
installed.
HEATING, VENTILATION AND AIR CONDITIONING (HVAC) 1A–77
(Charging amount of oil
to new compressor)
same as drained amount
90 cc (3.0 fl.oz)
Whenever contaminated
(Component parts to be
installed)
Evaporator
Condenser
Receiver/dryer
Refrigerant line (one
piece)
Compressor Leak Testing (External
and Internal)
Bench-Check Procedure
1. Install test plate J-39893 on rear head of compressor.
2. Using Refrigerant Recovery System, attach center
hose of manifold gage set on charging station to a
refrigerant drum standing in an upright drum.
3. Connect charging station high and low pressure lines
to corresponding fittings on test plate J-39893.
Suction port (low-side) of compressor has large
internal opening. Discharge port (high-side) has
smaller internal opening into compressor and deeper
recess.
4. Open low pressure control, high pressure control and
refrigerant control on charging station to allow
refrigerant vapor to flow into compressor.
5. Using a leak detector, check for leaks at pressure
relief valve, rear head switch location, compressor
front and rear head seals, center cylinder seal,
through bolt head gaskets and compressor shaft
seal. After checking, shut off low pressure control and
high-pressure control on charging station.
6. If an external leak is present, perform the necessary
corrective measures and recheck for leaks to make
certain the leak has been connected.
7. Recover the refrigerant.
8. Disconnect both hoses from the test plate J-39893.
9. Add 90 ml (3 oz.) new PAG lubricant to the
compressor assembly.
compressor assembly (not the crankshaft or drive
plate hub) slowly several turns to distribute oil to all
cylinder and piston areas.
10. Install a M9 1.25 threaded nut on the compressor
crankshaft if the drive plate and clutch assembly are
not installed.
11. Using a box-end wrench or socket and handle, rotate
the compressor crankshaft or clutch drive plate on the
crankshaft several turns to insure piston assembly to
cylinder wall lubrication.
12. Using Refrigerant Recovery System, connect the
charging station high-pressure line to the test plate
J-39893 high-side connector.
13. Using Refrigerant Recovery System, connect the
charging station low-pressure line to the low pressure
port of the test plate J-39893. Oil will drain out of the
compressor suction port if the compressor is
positioned with the suction port downward.
(Amount of Oil)
50 cc (1.7 fl. oz.)
30 cc (1.0 fl. oz.)
30 cc (1.0 fl. oz.)
10 cc (0.3 fl. oz.)
Rotate the complete