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. A R-134a refrigerant recov-
ery/recycling/charging station that meets SAE Stan-
dard J2210 must be used to evacuate the refrigerant
system. See the operating instructions supplied by
the equipment manufacturer for proper care and use
of this equipment. To evacuate the refrigerant sys-
tem, use the following procedure:
NOTE: When connecting the service equipment
couplings to the refrigerant system service ports,
be certain that the valve of each coupling is fully
closed. This will reduce the amount of effort
required to make the connection.
(1) Recover the refrigerant system (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE).
(2) Connect a suitable charging station, refrigerant
recovery machine or a manifold gauge set with vac-
uum pump and refrigerant recovery equipment.
(3) Open the suction and discharge valves and
start the vacuum pump. The vacuum pump should
run a minimum of 45 minutes prior to charge to
eliminate all moisture in system. When the suction
gauge reads -88 kPa (-26 in. Hg) vacuum or greater
for 30 minutes, close all valves and turn off vacuum
pump. If the system fails to reach specified vacuum,
the refrigerant system likely has a leak that must be
corrected. If the refrigerant system maintains speci-
fied vacuum for at least 30 minutes, start the vac-
uum pump, open the suction and discharge valves.
Then allow the system to evacuate an additional 10
minutes.
(4) Close all valves. Turn off and disconnect the
vacuum pump.
(5) Charge the refrigerant system (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE).REFRIGERANT SYSTEM CHARGE
WARNING: REFER TO THE APPLICABLE WARN-
INGS AND CAUTIONS FOR THIS SYSTEM BEFORE
PERFORMING THE FOLLOWING OPERATION (Refer
to 24 - HEATING & AIR CONDITIONING/PLUMBING -
FRONT - WARNING - A/C PLUMBING) and (Refer to
24 - HEATING & AIR CONDITIONING/PLUMBING -
FRONT - CAUTION - A/C PLUMBING).
After all refrigerant system leaks have been
repaired and the refrigerant system has been evacu-
ated, a refrigerant charge can be injected into the
system. For the proper amount of the refrigerant
charge, refer to REFRIGERANT CHARGE CAPAC-
ITY. A R-134a refrigerant recovery/recycling/charging
station that meets SAE Standard J2210 must be
used to charge the refrigerant system with R-134a
refrigerant. See the operating instructions supplied
by the equipment manufacturer for proper care and
use of this equipment.
REFRIGERANT CHARGE CAPACITY
NOTE: Always refer to the underhood HVAC Speci-
fication Label for the refrigerant fill specification of
the vehicle being serviced.
CHARGING PROCEDURE
CAUTION: A small amount of refrigerant oil is
removed from the A/C system each time the refrig-
erant system is recovered and evacuated. Before
charging the A/C system, you MUST replenish any
oil lost during the recovery process. Refer the
equipment manufacturer instructions for more infor-
mation.
(1) Evacuate the refrigerant system. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
FRONT/REFRIGERANT - STANDARD PROCE-
DURE - REFRIGERANT SYSTEM EVACUATE).
(2) A manifold gauge set and a R-134a refrigerant
recovery/recycling/charging station that meets SAE
Standard J2210 should still be connected to the
refrigerant system.
(3) Measure the proper amount of refrigerant and
heat it to 52É C (125É F) with the charging station.
See the operating instructions supplied by the equip-
ment manufacturer for proper use of this equipment.
RSPLUMBING - FRONT24-71
PLUMBING - FRONT (Continued)
OPERATION
R-134a refrigerant is not compatible with R-12
refrigerant in an air conditioning system. Even a
small amount of R-12 added to an R-134a refrigerant
system will cause compressor failure, refrigerant oil
sludge or poor air conditioning system performance.
In addition, the PolyAlkylene Glycol (PAG) synthetic
refrigerant oils used in an R-134a refrigerant system
are not compatible with the mineral-based refriger-
ant oils used in an R-12 refrigerant system. R-134a
refrigerant system service ports, service tool couplers
and refrigerant dispensing bottles have all been
designed with unique fittings to ensure that an
R-134a system is not accidentally contaminated with
the wrong refrigerant (R-12). There are also labels
posted in the engine compartment of the vehicle and
on the compressor identifying to service technicians
that the air conditioning system is equipped with
R-134a.
REFRIGERANT OIL
DESCRIPTION
The refrigerant oil used in R-134a refrigerant sys-
tems is a synthetic-based, PolyAlkylene Glycol (PAG),
wax-free lubricant. Mineral-based R-12 refrigerant
oils are not compatible with PAG oils, and should
never be introduced to an R-134a refrigerant system.
There are different PAG oils available, and each con-
tains a different additive package. The compressor
used in this vehicle is designed to use an ND-8 PAG
refrigerant oil. Use only refrigerant oil of this same
type to service the refrigerant system.
OPERATION
After performing any refrigerant recovery or recy-
cling operation, always replenish the refrigerant sys-
tem with the same amount of the recommended
refrigerant oil as was removed. Too little refrigerant
oil can cause compressor damage, and too much can
reduce air conditioning system performance. PAG
refrigerant oil is much more hygroscopic than min-
eral oil, and will absorb any moisture it comes into
contact with, even moisture in the air. The PAG oil
container should always be kept tightly capped until
it is ready to be used. After use, recap the oil con-
tainer immediately to prevent moisture contamina-
tion.
STANDARD PROCEDURE
REFRIGERANT OIL LEVEL
WARNING: REFER TO THE APPLICABLE WARN-
INGS AND CAUTIONS FOR THIS SYSTEM BEFORE
PERFORMING THE FOLLOWING OPERATION (Refer
to 24 - HEATING & AIR CONDITIONING/PLUMBING -
FRONT - WARNING - A/C PLUMBING) and (Refer to
24 - HEATING & AIR CONDITIONING/PLUMBING -
FRONT - CAUTION - A/C PLUMBING).
CAUTION: Use only PAG oils that are designed to
work with R-134a refrigerant and the A/C compres-
sor in the vehicle. Refer to the underhood A/C Sys-
tem Specification Label.
It is important to have the correct amount of lubri-
cant in the A/C refrigerant system to ensure proper
lubrication of the A/C compressor. Too little lubricant
will result in damage to the compressor. Too much
lubricant will reduce the cooling capacity of the A/C
system and consequently 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 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 moisture it comes
in contact with.
It will not be necessary to check the oil level in the
A/C compressor or to add oil, unless there has been
an oil loss. An oil loss may occur due to a rupture or
leak from a refrigerant line, connector fitting, compo-
nent or component seal. If a leak occurs, add 30 mil-
liliters (1 fluid ounce) of the recommended
refrigerant oil to the refrigerant system after the
repair has been made. Refrigerant oil loss will be evi-
dent at the leak point by the presence of a wet, shiny
surface around the leak.
REFRIGERANT OIL LEVEL CHECK
When an air conditioning system is first assembled
at the factory, all components (except the A/C com-
pressor) are refrigerant oil free. After the refrigerant
system has been charged with (R-134a) refrigerant
and operated, the oil in the A/C compressor is dis-
persed through the lines and components. The A/C
evaporator, A/C 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
24 - 94 PLUMBING - FRONTRS
REFRIGERANT (Continued)
rest of the system must be drained from the replace-
ment A/C compressor. The oil capacity of the system,
minus the amount of oil still in the remaining com-
ponents (refer to the oil capacity chart below) can be
measured and poured into the suction port of the A/C
compressor. When a line or component has ruptured
and oil has escaped, the receiver/drier must be
replaced along with the ruptured component.
Example: On this A/C system the front A/C evapo-
rator retains 50 ml. (1.7 oz.). The A/C condenser
retains 50 ml. (1.7 oz.) of oil, and front A/C system oil
capacity is 180 ml. (6.1 oz.).
180 ml. ± 100 ml. = 80 ml. (2.7 oz.).
A/C COMPONENT REFRIGERANT OIL
CAPACITIES
Front A/C Front & Rear
A/C
COMPONENT ml fl oz ml fl oz
Total System Fill 180 6.1 230 7.8
Receiver/Drier 25 0.8 25 0.8
A/C Condenser 50 1.7 50 1.7
Front Evaporator 50 1.7 50 1.7
Rear Evap. (including
underbody lines)N/A N/A 50 1.7
A/C Compressor Drain and measure the oil
from the old A/C compressor
- See text above.
VERIFY REFRIGERANT LUBRICANT LEVEL
(1) Recover the refrigerant from the system.
(2) Disconnect the refrigerant lines from the A/C
compressor. Cap open lines to prevent moisture from
entering the system.
(3) Remove A/C compressor from the vehicle.
(4) From the suction and discharge ports on the
A/C compressor, drain the lubricant from the com-
pressor.
(5) Add the system capacity minus the capacity of
the components that have not been replaced. Refer to
the A/C Component Refrigerant Oil Capacities chart.
Add lubricant through the suction and discharge
ports on the A/C compressor.
(6) Install the A/C compressor and connect the
refrigerant lines. Then evacuate and charge refriger-
ant 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
A/C compressor is being installed, drain the lubricant
from the used compressor, measure the amount
drained and discard the used lubricant. Drain the
lubricant from the new A/C compressor into a cleancontainer. Return the amount of lubricant measured
from the used compressor, plus the amount reclaimed
from the system back into the new A/C compressor.
Refer to the reclaim/recycling equipment manufactur-
ers instructions.
SERVICE PORT VALVE CORE
DESCRIPTION
A/C SERVICE PORT VALVE CORES
The low side valve is located on the suction line
near the A/C compressor. The low side A/C service
port valve core is a serviceable item. The high side
A/C service port valve core is located on the liquid
line fitting attached to the top of the receiver/drier.
The high side A/C service port valve core is not a sep-
arate serviceable item. If the high side service port
valve core is faulty or damaged, the front section of
the liquid line will require replacement.
REMOVAL
WARNING: REFER TO THE APPLICABLE WARN-
INGS AND CAUTIONS FOR THIS SYSTEM BEFORE
PERFORMING THE FOLLOWING OPERATION (Refer
to 24 - HEATING & AIR CONDITIONING/PLUMBING -
FRONT - WARNING - A/C PLUMBING) and (Refer to
24 - HEATING & AIR CONDITIONING/PLUMBING -
FRONT - CAUTION - A/C PLUMBING).
(1) Recover the refrigerant from the refrigerant
system (Refer to 24 - HEATING & AIR CONDITION-
ING/PLUMBING - FRONT/REFRIGERANT - STAN-
DARD PROCEDURE - REFRIGERANT
RECOVERY).
(2) Using a standard Schrader-type valve core tool,
remove the valve core from the low side A/C service
port located on the suction line.
(3) Install a plug in or tape over the opened low
side A/C service port.
INSTALLATION
(1) Lubricate the low side A/C service port valve
core with clean refrigerant oil prior to installation.
Use only refrigerant oil of the type recommended for
the compressor in the vehicle.
(2) Remove the tape or plug from the A/C service
port located on the suction line near the A/C com-
pressor.
(3) Using a standard Schrader-type valve core tool,
install and tighten the replacement valve core into
the low side A/C service port.
RSPLUMBING - FRONT24-95
REFRIGERANT OIL (Continued)