Checking And Adjusting For Compressor Replacement; Contamination Of Compressor Oil; Oil Return Operation; Replacement Of Component Parts - Isuzu 1999 RODEO Workshop Manual

2. Drain the compressor oil and measure the extracted
oil with a measuring cylinder.
3. Check the oil for contamination.
4. If more than 90 cc (3.0 fl. oz.) of oil is extracted from
the compressor, supply the same amount of oil to the
compressor to be installed.
5. If the amount of oil extracted is less than 90 cc (3.0 fl.
oz.), recheck the compressor oil in the following
order.
6. Supply 90 cc (3.0 fl. oz.) of oil to the compressor and
install it onto the vehicle.
7. Evacuate and recharge with the proper amount of
refrigerant.
8. Perform the oil return operation.
9. Remove the compressor and recheck the amount of
oil.
10. Adjust the compressor oil, if necessary.
(Collected Amount)
more than 90 cc
(3.0 fl.oz)
less than 90 cc (3.0 fl.oz)
Checking and Adjusting for
Compressor Replacement
150 cc (5.0 fl.oz.) of oil is charged in compressor (service
parts). So it is necessary to drain the proper amount of oil
from the new compressor.
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)
less than 90 cc (3.0 fl.oz)
more 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:
f The capacity of the oil has increased.
HEATING, VENTILATION AND AIR CONDITIONING (HVAC) 1A–71
(Charging Amount)
same as collected
amount
90 cc (3.0 fl.oz)
(Draining amount of oil
from new compressor)
Same as drained
amount
90 cc (3.0 fl.oz)
f The oil has changed to red.
f 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.
(Component parts to be
installed)
Evaporator
Condenser
Receiver/dryer
Refrigerant line (one
piece)
Whenever contaminated
(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.)