REFRIGERANT OIL LEVEL CHECK
When an air conditioning system is first assembled,
all components (except the compressor) are refrigerant
oil free. After the system has been charged with
(R-134a) refrigerant and operated, the oil in the com-
pressor is dispersed through the lines and compo-
nents. The evaporator, condenser, and receiver/drier
will retain a significant amount of oil. Refer to the A/C
Component Refrigerant Oil Capacities table. When a
component is replaced, the specified amount of refrig-
erant oil must be added. When the compressor is
replaced, the amount of oil that is retained in the rest
of the system must be drained from the replacement
compressor. When a line or component has ruptured
and oil has escaped, the compressor should be
removed and drained. The receiver/drier must be
replaced along with the ruptured part. The oil capac-
ity of the system, minus the amount of oil still in the
remaining components, can be measured and poured
into the suction port of the compressor.
Example: On an A/C system the evaporator retains
60 ml. (2 oz.). The condenser retains 30 ml. (1 oz.) of
oil, and system capacity may be 150 ml. (5.00 oz.) of oil.
150 ml. minus 90 ml. equals 60 ml. (2.00 oz.).
CAUTION: The refrigerant oil used in a R-134a A/C
system
is
unique.
Use
only
oils
which
were
designed to work with R-134a refrigerant. The oil
designated for this vehicle is SP-15 PAG (polyalky-
lene glycol).
VERIFY REFRIGERANT LUBRICANT LEVEL
(1) Discharge refrigerant system using a recycling/
reclaiming equipment if a charge is present.
(2) Disconnect refrigerant lines from A/C compres-
sor. Cap the open lines to prevent moisture from
entering system.
(3) Remove compressor from vehicle.
(4) From suction and discharge ports on top of
compressor, drain lubricant from compressor.
(5) Add system capacity minus the capacity of
components that have not been replaced. Refer to the
A/C Component Refrigerant Oil Capacities chart
above. Add lubricant through the suction and dis-
charge ports on compressor. This is not to exceed 150
ml. (5.00 oz.) in total.
(6) Install
compressor
and
connect
refrigerant
lines. Then evacuate and charge refrigerant system.
(7) Most reclaim/recycling equipment will measure
the lubricant being removed. This is the amount of
lubricant to be added back to the system. If a new
compressor is being installed, drain lubricant from
old compressor, measure the amount drained and dis-
card old lubricant. Drain the lubricant from the new
compressor
into
a
clean
container.
Return
the
amount of lubricant measured from the old compres-
sor, plus the amount reclaimed from the system back
into the new compressor.
THERMAL LIMITER SWITCH
(1) Unplug Thermal Limiter wiring connector.
(2) With
an
ohmmeter
check
for
continuity
between the two terminals. If no continuity is
present, replace the compressor.
(3) The Thermal Limiter is calibrated to open and
close at:
• Open circuit (no continuity) at 122 to 128°C (252
to 262°F)
• Close circuit (continuity) at 106 to 116°C (225 to
235°F)
There is no serviceability of the thermal lim-
iter switch. If the thermal limiter switch fails,
the compressor must be replaced. To replace
the compressor, refer to Compressor Removal
and Installation in this section.
SERVICE PROCEDURES
EVACUATING REFRIGERANT SYSTEM
NOTE: Special effort must be used to prevent mois-
ture from entering the A/C system oil. Moisture in
the oil is very difficult to remove and will cause a
reliability problem with the compressor.
If a compressor designed to use R-134a refrigerant
is left open to the atmosphere for an extended period
of time. It is recommended that the refrigerant oil be
drained and replaced with new oil or a new compres-
sor be used. This will eliminate the possibility of con-
taminating the refrigerant system.
If the refrigerant system has been open to the
atmosphere, it must be evacuated before the system
can be filled. Moisture and air mixed with the refrig-
erant will raise the compressor head pressure above
acceptable operating levels. This will reduce the per-
formance of the air conditioner and damage the com-
pressor. Moisture will boil at near room temperature
when exposed to vacuum. To evacuate the refrigerant
system:
A/C COMPONENT REFRIGERANT OIL
CAPACITIES
COMPONENT NAME
ml.
oz.
Total Air Conditioning System
150 ml.
5.00 oz.
Condenser
30 ml.
1.00 oz.
Evaporator
59 ml.
2.00 oz.
Filter/Drier
30 ml.
1.00 oz.
Line Blown
44 ml.
1.50 oz.
JX
HEATING AND AIR CONDITIONING
24 - 9
DIAGNOSIS AND TESTING (Continued)