the refrigerant between the various air conditioning
system components. A barrier hose design with a
nylon tube, which is sandwiched between rubber lay-
ers, is used for the R-134a air conditioning system on
this vehicle. This nylon tube helps to further contain
the R-134a refrigerant, which has a smaller molecu-
lar structure than R-12 refrigerant. The ends of the

refrigerant hoses are made from lightweight alumi-
num or steel, and commonly use braze-less fittings.

Any kinks or sharp bends in the refrigerant plumb-

ing will reduce the capacity of the entire air condi-
tioning system. Kinks and sharp bends reduce the
flow of refrigerant in the system. A good rule for the
flexible hose refrigerant lines is to keep the radius of
all bends at least ten times the diameter of the hose.
In addition, the flexible hose refrigerant lines should
be routed so they are at least 80 millimeters (3
inches) from the exhaust manifold (Whenever possi-
ble).

PLUMBING

24 - 27

OPERATION - REFRIGERANT LINE

High pressures are produced in the refrigerant sys-

tem when the air conditioning compressor is operat-
ing. Extreme care must be exercised to make sure
that each of the refrigerant system connections is
pressure-tight and leak free. It is a good practice to
inspect all flexible hose refrigerant lines at least once
a year to make sure they are in good condition and
properly routed.

The refrigerant lines and hoses are coupled with

other components of the HVAC system with peanut-
block style fittings. A stat-O seal type flat steel gas-
ket with a captured compressible O-ring, is used to
mate plumbing lines with A/C components to ensure
the integrity of the refrigerant system.

The refrigerant lines and hoses cannot be repaired

and, if faulty or damaged, they must be replaced.

WARNING

WARNING: WEAR EYE PROTECTION WHEN SER-
VICING THE AIR CONDITIONING REFRIGERANT
SYSTEM. SERIOUS EYE INJURY CAN RESULT
FROM EYE CONTACT WITH REFRIGERANT. IF EYE
CONTACT IS MADE, SEEK MEDICAL ATTENTION
IMMEDIATELY.
DO NOT EXPOSE REFRIGERANT TO OPEN FLAME.
POISONOUS GAS IS CREATED WHEN REFRIGER-
ANT IS BURNED. AN ELECTRONIC TYPE LEAK
DETECTOR IS RECOMMENDED.
LARGE AMOUNTS OF REFRIGERANT RELEASED
IN A CLOSED WORK AREA WILL DISPLACE THE
OXYGEN AND CAUSE SUFFOCATION.
THE EVAPORATION RATE OF REFRIGERANT AT
AVERAGE

TEMPERATURE

AND

ALTITUDE

EXTREMELY HIGH. AS A RESULT, ANYTHING THAT
COMES IN CONTACT WITH THE REFRIGERANT
WILL FREEZE. ALWAYS PROTECT SKIN OR DELI-
CATE OBJECTS FROM DIRECT CONTACT WITH
REFRIGERANT. R-134a SERVICE EQUIPMENT OR
VEHICLE A/C SYSTEM SHOULD NOT BE PRES-
SURE TESTED OR LEAK TESTED WITH COM-
PRESSED AIR.
SOME MIXTURES OF AIR AND R-134a HAVE BEEN
SHOWN

COMBUSTIBLE

ELEVATED

PRESSURES.

THESE

MIXTURES

ARE

POTEN-

TIALLY DANGEROUS AND MAY RESULT IN FIRE OR
EXPLOSION

CAUSING

INJURY

PROPERTY

DAMAGE.
ANTIFREEZE IS AN ETHYLENE GLYCOL BASE
COOLANT AND IS HARMFUL IF SWALLOWED OR
INHALED. SEEK MEDICAL ATTENTION IMMEDI-
ATELY IF SWALLOWED OR INHALED. DO NOT
STORE IN OPEN OR UNMARKED CONTAINERS.
WASH SKIN AND CLOTHING THOROUGHLY AFTER
COMING IN CONTACT WITH ETHYLENE GLYCOL.

KEEP OUT OF REACH OF CHILDREN AND PETS.
DO NOT OPEN A COOLING SYSTEM WHEN THE
ENGINE IS AT RUNNING TEMPERATURE. PER-
SONAL INJURY CAN RESULT.

CAUTION

REFRIGERANT SYSTEM PRECAUTIONS

CAUTION:: The system must be completely empty
before opening any fitting or connection in the
refrigeration system. Open fittings with caution
even after the system has been emptied. If any
pressure

noticed

fitting

loosened,

retighten fitting and evacuate the system again.
A good rule for the flexible hose lines is to keep the
radius of all bends at least 10 times the diameter of
the hose. Sharper bends will reduce the flow of
refrigerant. The flexible hose lines should be routed
so they are at least 3 inches (80 mm) from the
exhaust manifold. Inspect all flexible hose lines to
make sure they are in good condition and properly
routed.
The use of correct wrenches when making connec-
tions is very important. Improper wrenches or
improper use of wrenches can damage the fittings.
The internal parts of the A/C system will remain sta-
ble as long as moisture-free refrigerant and refrig-
erant

oil

used. Abnormal

amounts

dirt,

moisture or air can upset the chemical stability.
This may cause operational troubles or even seri-
ous damage if present in more than very small
quantities.
When opening a refrigeration system, have every-
thing you will need to repair the system ready. This
will minimize the amount of time the system must
be opened. Cap or plug all lines and fittings as
soon as they are opened. This will help prevent the
entrance of dirt and moisture. All new lines and
components should be capped or sealed until they
are ready to be used.
All tools, including the refrigerant dispensing mani-
fold, the manifold gauge set, and test hoses should
be kept clean and dry.

REFRIGERANT SYSTEM HOSES/LINES/TUBES/
PRECAUTIONS

Kinks in the refrigerant tubing or sharp bends in

the refrigerant hose lines will greatly reduce the
capacity of the entire system.

High pressures are produced in the system when it

is operating. Extreme care must be exercised to make
sure that all connections are pressure tight. Dirt and
moisture can enter the system when it is opened for
repair or replacement of lines or components. The

24 - 28

PLUMBING

PLUMBING (Continued)

refrigerant oil will absorb moisture readily out of the
air. This moisture will convert into acids within a
closed system.

DIAGNOSIS AND TESTING - REFRIGERANT
SYSTEM LEAKS

WARNING: REVIEW THE WARNINGS IN THE FRONT
OF THIS SECTION BEFORE PERFORMING THE
FOLLOWING OPERATION. (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - WARNING)

If the refrigerant system is empty or low in refrig-

erant charge, a leak at any line fitting or component
seal is likely. A review of the fittings, lines and com-
ponents for oily residue is an indication of the leak
location. To detect a leak in the refrigerant system,
perform one of the following procedures as indicated
by the symptoms.

EMPTY REFRIGERANT SYSTEM LEAK TEST

(1) Evacuate the refrigerant system (minimum

evacuation time of 15 min.) to the lowest degree of
vacuum possible (approx. 28 in Hg.). (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE) Determine if the system
holds a vacuum for at least 15 minutes after pump is
off. If vacuum is held, a leak is probably not present.
If system will not maintain vacuum level, proceed
with this procedure.

(2) Prepare a .284 Kg. (10 oz.) refrigerant charge

to be injected into the system.

(3) Connect and dispense .284 Kg. (10 oz.) of

refrigerant into the evacuated refrigerant system.

(4) Proceed to Step 2 of Low Refrigerant Level

Leak Test.

LOW REFRIGERANT LEVEL LEAK TEST

(1) Determine if there is any (R-134a) refrigerant

in the system.

(2) Position the vehicle in a wind free work area.

This will aid in detecting small leaks.

(3) Bring the refrigerant system up to operating

temperature and pressure. This is done by allowing
the engine to run for five minutes with the system
set to the following:

• Transaxle in Park

• Engine Idling

• A/C Controls Set in 100 percent outside air

(Recirculation position)

• Blower switch in the high A/C position

• A/C in the ON position

• Open all windows

CAUTION: A leak detector designed for R-12 refrig-
erant may not detect leaks in a R-134a refrigerant
system. Check specifications on leak detector.

(4) Shut off the vehicle and wait 2 to 7 minutes.

Then use an Electronic Leak Detector that is
designed to detect R-134a type refrigerant and search
for leaks. Fittings, lines, or components that appear
to be oily usually indicates a refrigerant leak. To
inspect the evaporator core for leaks, insert the leak
detector probe into the drain tube opening or a heat
duct.

NOTE: If leak is not detected but known to exist,
further diagnosis may be necessary using a refrig-
erant dye and the recovery machine. Refer to recov-
ery machine instructions for proper dye injection
procedures.

STANDARD PROCEDURE

STANDARD PROCEDURE - REFRIGERANT
SYSTEM SERVICE EQUIPMENT

WARNING: REVIEW THE WARNINGS IN THE FRONT
OF THIS SECTION BEFORE PERFORMING THE
FOLLOWING OPERATION. (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - WARNING)

When servicing the air conditioning system, a

R-134a refrigerant recovery/recycling/charging sta-
tion that meets SAE Standard J2210 must be used.
Contact an automotive service equipment supplier for
refrigerant

recovery/recycling/charging

equipment.

Refer to the operating instructions supplied by the
equipment manufacturer for proper care and use of
this equipment.

A manifold gauge set may be needed with some

recovery/recycling/charging equipment (Fig. 1). The
service hoses on the gauge set being used should
have manual (turn wheel), or automatic back-flow
valves at the service port connector ends. This will
prevent refrigerant from being released into the
atmosphere.

MANIFOLD GAUGE SET CONNECTIONS

CAUTION: Do not use an R-12 manifold gauge set
on an R-134a system. The refrigerants are not com-
patible and system damage will result.

LOW PRESSURE GAUGE HOSE The low pressure

hose (Blue with Black stripe) attaches to the suction
service port. This port is located on the suction line
between the accumulator outlet and the compressor.

PLUMBING

24 - 29

PLUMBING (Continued)

HIGH PRESSURE GAUGE HOSE The high pres-

sure hose (Red with Black stripe) attaches to the dis-
charge service port. This port is located on the
discharge line between the compressor and the con-
denser inlet.

RECOVERY/RECYCLING/EVACUATION/CHARG-

ING HOSE The center manifold hose (Yellow, or
White, with Black stripe) is used to recover, evacu-
ate, and charge the refrigerant system. When the low
or high pressure valves on the manifold gauge set
are opened, the refrigerant in the system will escape
through this hose.

STANDARD PROCEDURE - REFRIGERANT
RECOVERY

WARNING: REVIEW THE WARNINGS IN THE FRONT
OF THIS SECTION BEFORE PERFORMING THE
FOLLOWING OPERATION. (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - WARNING)

A R-134a refrigerant recovery/recycling/charging

station that meets SAE Standard J2210 must be
used to recover the refrigerant from an R-134a refrig-
erant system. Refer to the operating instructions sup-
plied by the equipment manufacturer for the proper
care and use of this equipment.

STANDARD PROCEDURE - REFRIGERANT
SYSTEM EVACUATE

WARNING: REVIEW THE WARNINGS IN THE FRONT
OF THIS SECTION BEFORE PERFORMING THE
FOLLOWING OPERATION. (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - WARNING)

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:

NOTE: When connecting the service equipment
coupling to the line fitting, verify that the valve of
the coupling is fully closed. This will reduce the
amount of effort required to make the connection.

(1) Connect a suitable charging station, refrigerant

recovery machine, or a manifold gauge set with vac-
uum pump (Fig. 2).

(2) Open suction and discharge valves and start

vacuum pump. The vacuum pump should run a min-
imum of 45 minutes prior to charge, to eliminate all
moisture in system. When suction gauge reads -88
kPa (-26 in. Hg) vacuum or greater for 45 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
specified vacuum for at least 30 minutes, start the
vacuum pump, open the suction and discharge
valves. Then allow the system to evacuate an addi-
tional 10 minutes.

(3) Close all valves. Turn off and disconnect the

vacuum pump.

(4) The refrigerant system is prepared to be

charged with refrigerant.

Fig. 1 MANIFOLD GAUGE SET - TYPICAL

1 - HIGH PRESSURE GAUGE
2 - VALVE
3 - VACUUM/REFRIGERANT HOSE (YELLOW W/ BLACK STRIPE)
4 - HIGH PRESSURE HOSE (RED W/ BLACK STRIPE)
5 - LOW PRESSURE HOSE (BLUE W/ BLACK STRIPE)
6 - VALVE
7 - LOW PRESSURE GAUGE

24 - 30

PLUMBING

PLUMBING (Continued)

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