SYSTEM OIL LEVEL
It is important to have the correct amount of lubri-
cant in the A/C system to ensure proper lubrication
of the compressor. Too little lubricant will result in
damage to the compressor. Too much lubricant will
reduce the cooling capacity of the system and conse-
quently result in higher discharge air temperatures.
The lubricant used in the compressor is polyalka-
lene glycol PAG lubricant. Only the refrigerant lubri-
cant approved for use with this vehicle (ND8 PAG
oil) should be used to service the system. Do not use
any other lubricant. The lubricant container should
be kept tightly capped until it is ready for use.
Refrigerant lubricant will quickly absorb any mois-
ture it comes in contact with.
It is not necessary to check or add lubricant unless
it has been lost. Lubricant loss at the leak point will
be evident by the presence of a wet, shiny surface
around the leak.
REFRIGERANT OIL LEVEL CHECK
When an air conditioning system is first assem-
bled, 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 compressor is dispersed through the lines
and components. The evaporator, condenser, and
receiver/drier will retain a significant amount of oil.
Refer to the A/C Component Refrigerant Oil Capaci-
ties table. When a component is replaced, the speci-
fied amount of refrigerant 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. The oil capacity of
the system, minus the amount of oil still in the
remaining components (refer to the oil capacity chart
below) can be measured and poured into the suction
port of the compressor. When a line or component
has ruptured and oil has escaped, the receiver/drier
must be replaced along with the ruptured part.
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 ND 8 PAG (polyalka-
lene glycol).
VERIFY REFRIGERANT ND8 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 amount of lubri-
cant should 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.
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-
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.
300M
HEATING AND AIR CONDITIONING
24 - 11
DIAGNOSIS AND TESTING (Continued)