LOOSEN THE COOLANT PRESSURE CAP, CYLIN-
DER BLOCK DRAIN PLUGS, RADIATOR DRAIN,
RADIATOR HOSES, HEATER HOSES, OR HOSE
CLAMPS WHILE THE SYSTEM IS HOT AND UNDER
PRESSURE. FAILURE TO OBSERVE THIS WARNING
CAN RESULT IN SERIOUS BURNS FROM THE
HEATED ENGINE COOLANT. ALLOW THE VEHICLE
TO

COOL

FOR A MINIMUM

MINUTES

BEFORE OPENING THE COOLING SYSTEM FOR
SERVICE.

WARNING: THE ENGINE COOLING SYSTEM CON-
TAINS ANTIFREEZE. ANTIFREEZE IS AN ETHYLENE
GLYCOL BASED COOLANT AND IS HARMFUL IF
SWALLOWED OR IF THE VAPORS ARE INHALED. IF
SWALLOWED, DRINK TWO GLASSES OF WATER
AND INDUCE VOMITING. IF VAPORS ARE INHALED,
MOVE TO AN AREA FOR FRESH AIR. SEEK MEDI-
CAL ATTENTION IMMEDIATELY. 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.

WARNING:

DISPOSE

ETHYLENE

GLYCOL

BASED COOLANT PROPERLY. CONTACT YOUR
DEALER OR A LOCAL GOVERNMENT AGENCY FOR
THE LOCATION OF AN APPROVED ETHYLENE GLY-
COL COLLECTION AND/OR RECYCLING CENTER IN
YOUR AREA.

WARNING - A/C PLUMBING

WARNING:: THE AIR CONDITIONING SYSTEM CON-
TAINS REFRIGERANT UNDER HIGH PRESSURE.
SEVERE PERSONAL INJURY MAY RESULT FROM
IMPROPER

SERVICE

PROCEDURES.

REPAIRS

SHOULD ONLY BE PERFORMED BY QUALIFIED
SERVICE PERSONNEL.

WARNING: AVOID BREATHING THE REFRIGERANT
AND REFRIGERANT OIL VAPOR OR MIST. EXPO-
SURE MAY IRRITATE THE EYES, NOSE, AND/OR

THROAT. WEAR EYE PROTECTION WHEN SERVIC-
ING THE AIR CONDITIONING REFRIGERANT SYS-
TEM. SERIOUS EYE INJURY CAN RESULT FROM
DIRECT CONTACT WITH THE REFRIGERANT. IF
EYE CONTACT OCCURS, SEEK MEDICAL ATTEN-
TION IMMEDIATELY.

WARNING: DO NOT EXPOSE THE REFRIGERANT
TO OPEN FLAME. POISONOUS GAS IS CREATED
WHEN

REFRIGERANT

BURNED.

ELEC-

TRONIC LEAK DETECTOR IS RECOMMENDED.

WARNING: IF ACCIDENTAL SYSTEM DISCHARGE
OCCURS, VENTILATE THE WORK AREA BEFORE
RESUMING

SERVICE.

LARGE

AMOUNTS

REFRIGERANT RELEASED IN A CLOSED WORK
AREA WILL DISPLACE THE OXYGEN AND CAUSE
SUFFOCATION.

WARNING: THE EVAPORATION RATE OF R-134a
REFRIGERANT AT AVERAGE TEMPERATURE AND
ALTITUDE IS EXTREMELY HIGH. AS A RESULT,
ANYTHING THAT COMES IN CONTACT WITH THE
REFRIGERANT WILL FREEZE. ALWAYS PROTECT
THE SKIN OR DELICATE OBJECTS FROM DIRECT
CONTACT WITH THE REFRIGERANT.

WARNING: THE R-134a SERVICE EQUIPMENT OR
THE VEHICLE REFRIGERANT SYSTEM SHOULD
NOT BE PRESSURE TESTED OR LEAK TESTED
WITH COMPRESSED AIR. SOME MIXTURES OF AIR
AND R-134a HAVE BEEN SHOWN TO BE COMBUS-
TIBLE AT ELEVATED PRESSURES. THESE MIX-
TURES ARE POTENTIALLY DANGEROUS, AND MAY
RESULT IN FIRE OR EXPLOSION CAUSING INJURY
OR PROPERTY DAMAGE.

CAUTION - A/C PLUMBING

CAUTION:: Liquid refrigerant is corrosive to metal
surfaces. Follow the operating instructions supplied
with the service equipment being used.

CAUTION: Never add R-12 to a refrigerant system
designed to use R-134a. Damage to the system will
result.

CAUTION: R-12 refrigerant oil must not be mixed
with R-134a refrigerant oil. They are not compatible.

PLUMBING - FRONT

24 - 61

CAUTION: Do not use R-12 equipment or parts on
the R-134a system. Damage to the system will
result. All parts, tools, and equipment must be
designed for R-134a refrigerant.

CAUTION: Do not discharge refrigerant into the
atmosphere. Use an R-134a refrigerant recovery/re-
cycling device that meets SAE Standard J2210.

CAUTION: The refrigerant must be recovered com-
pletely from the system before opening any fitting
or connection. Open the fittings with caution, even
after the system has been discharged. If any pres-
sure is noticed as a fitting is loosened, tighten the
fitting and recover the refrigerant from the system
again.

CAUTION: The refrigerant system must always be
evacuated before charging.

CAUTION: Do not overcharge the refrigerant sys-
tem. This will cause excessive compressor head
pressure and can cause noise and system failure.

CAUTION: Do not open the refrigerant system or
remove the sealing caps from a replacement com-
ponent until it is to be installed. This will prevent
contamination in the system.

CAUTION:

Before

disconnecting

component,

clean the outside of the fittings thoroughly to pre-
vent contamination from entering the refrigerant
system.

CAUTION: When it is necessary to open the refrig-
erant system, have everything needed to service
the system ready. Immediately after disconnecting a
component from the refrigerant system, seal the
open fittings with a cap or plug to prevent the
entrance of dirt and moisture. The refrigerant sys-
tem should not be left open to the atmosphere any
longer than necessary.

CAUTION: Before connecting an open refrigerant
fitting, always install a new seal and or gasket. All
fittings with O-rings need to be coated with refrig-
erant oil before installation. Use only O-rings that
are the correct size and approved for use with
R-134a refrigerant. Failure to do so may result in a
leak. Coat the fitting and seal with clean refrigerant
oil before connecting. Unified plumbing connec-

tions with gaskets cannot be serviced with O-rings.
The gaskets are not reusable and new gaskets do
not require lubrication before installing.

CAUTION: When installing a refrigerant line, avoid
sharp bends that may restrict refrigerant flow. 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. Sharp bends will reduce the
flow of refrigerant.

CAUTION: Position the refrigerant lines away from
exhaust system components or any sharp edges,
which may damage the line. The flexible hose lines
should be routed so they are at least 80 millimeters
(3 inches) from the exhaust manifold. Inspect all
flexible refrigerant system hose lines at least once
a year to make sure they are in good condition and
properly routed.

CAUTION: High pressures are produced in the
refrigerant system when it is operating. Extreme
care must be exercised to make sure that all refrig-
erant system connections are pressure tight.

CAUTION: Tighten refrigerant fittings only to the
specified torque. The aluminum fittings used in the
refrigerant system will not tolerate overtightening.

CAUTION: When disconnecting a refrigerant fitting,
use a wrench on both halves of the fitting. This will
prevent twisting of the refrigerant lines or tubes.

CAUTION: Refrigerant oil will absorb moisture from
the atmosphere if left uncapped. Do not open a
container of refrigerant oil until you are ready to
use it. Replace the cap on the oil container immedi-
ately after using. Store refrigerant oil only in a
clean, airtight, and moisture-free container.

CAUTION: All tools, including the refrigerant recy-
cling equipment, the manifold gauge set, and test
hoses should be kept clean and dry. Keep the work
area clean. Contamination of the refrigerant system
through careless work habits must be avoided. The
refrigerant system will remain chemically stable as
long as pure, moisture-free R-134a refrigerant and
refrigerant oil is used. Dirt, moisture, or air can
upset this chemical stability. Operational troubles
or serious damage can occur if foreign material is
introduced to the refrigerant system.

24 - 62

PLUMBING - FRONT

PLUMBING - FRONT (Continued)

A/C COMPRESSOR

DESCRIPTION

All vehicles use the Nippondenso 10S20 compres-

sor. This compressor use an aluminum swash plate,
teflon coated pistons and aluminum sleeveless cylin-
der walls. This compressor includes an integral high
pressure relief valve. The compressor is secured low
in the right front corner of the engine compartment
to a mounting bracket on the cylinder block (2.4L
engine), or directly to the cylinder block (3.3L and
3.8L engines) is integral to the compressor. This com-
pressor cannot be repaired. If faulty or damaged, the
entire compressor must be replaced. The compressor
clutch, pulley, and clutch coil are available for service
replacement.

OPERATION

The compressor is driven by the engine through an

electric clutch, drive pulley and belt arrangement.
The compressor is lubricated by refrigerant oil that is
circulated throughout the refrigerant system with the
refrigerant. The compressor draws in low-pressure
refrigerant vapor from the evaporator through its
suction port. It then compresses the refrigerant into
a high-pressure, high-temperature refrigerant vapor.
The compressor pumps high-pressure refrigerant
vapor to the condenser through the compressor dis-
charge port. The mechanical high pressure relief
valve is designed to vent refrigerant from the system
to protect against damage to the compressor or other
system components, caused by condenser air flow
restrictions or an overcharge of refrigerant. The valve
only vents enough refrigerant to reduce the system
pressure, then re-seats itself. The valve opens at a
discharge pressure of 3445 to 4135 kPA (500 to 600
psi) or above, and closes when a minimum discharge
pressure of 2756 kPa (400 psi) is reached.

DIAGNOSIS AND TESTING - COMPRESSOR
NOISE DIAGNOSIS

Excessive noise while the air conditioning compres-

sor is operating can be caused by loose compressor
mounts, a loose compressor clutch, or high operating
pressures in the refrigerant system. Verify compres-
sor drive belt condition, proper compressor mounting,
correct refrigerant charge level, and compressor head
pressure before compressor repair is performed.

With the close tolerances within the compressor, it

is possible to experience a temporary lockup. The
longer the compressor is inactive, the more likely the
condition is to occur. This condition is the result of
normal refrigerant migration within the refrigerant
system caused by ambient temperature changes. The

refrigerant migration may wash the refrigerant oil
out of the compressor.

NOTE: Prior to a vehicle being removed from ser-
vice or stored for more than two weeks, the com-
pressor should be operated to ensure adequate
refrigerant oil distribution throughout the system
components. Turn on the air conditioner for a min-
imum of five minutes with outside air and the high-
est blower speed selected.

BELT NOISE

If the compressor drive belt slips at initial start-up,

it does not necessarily mean the compressor has
failed. The following procedure can be used to iden-
tify a compressor drive belt noise problem.

A. Start the vehicle and run at idle.
B. Turn the air conditioner On and listen for belt

squeal.

C. If belt squeal is heard, turn the air conditioner

Off immediately.

If the belt squeal stops when the air conditioner is

turned Off, perform the following repair procedures.

(1) Using an appropriate sized oil filter wrench or

a strap wrench, grasp the outer diameter of the com-
pressor clutch hub. While facing the compressor,
rotate the hub clockwise, then counterclockwise. If
the hub rotates, proceed to the next step. If the hub
will not rotate, the compressor is internally damaged,
and must be replaced.

(2) Turn the hub clockwise five complete revolu-

tions and remove the tool.

(3) Start the vehicle and run at idle.
(4) Turn the air conditioner On. Observe the com-

pressor and the system for normal operation, noting
cooling performance and noise levels. Operate for five
minutes before turning the air conditioner Off. If
acceptable cooling performance is observed during
compressor operation, the compressor does not need
to be replaced.

(5) Inspect the drive belt for wear, damage, and

proper tension. (Refer to 7 - COOLING/ACCESSORY
DRIVE/DRIVE BELTS - DIAGNOSIS AND TEST-
ING).

PLUMBING - FRONT

24 - 63

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