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
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.
²Start the vehicle and run at idle.²Turn the air conditioner On and listen for belt
squeal.
²If 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).
REMOVAL - COMPRESSOR
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 CONDI-
TIONING/PLUMBING - FRONT/REFRIGERANT -
STANDARD PROCEDURE - REFRIGERANT
RECOVERY).
(2) Disconnect and isolate the battery negative
cable.
(3) Remove the nut that secures the suction line
fitting to the top of the compressor.
(4) Disconnect the suction line fitting from the
compressor suction port.
(5) Remove the seal from the suction line fitting
and discard.
(6) Install plugs in, or tape over the opened suc-
tion line fitting and the compressor suction port.
(7) Remove the nut that secures the discharge line
fitting to the top of the compressor.
(8) Disconnect the discharge line fitting from the
compressor discharge port.
RSPLUMBING - FRONT24-65
COMPRESSOR (Continued)
ProCarManuals.com
(9) Remove the seal from the discharge line fitting
and discard.
(10) Install plugs in, or tape over the opened dis-
charge line fitting and the compressor discharge port.
(11) Raise and support the vehicle.
(12) Remove the serpentine accessory drive belt
from the front of the engine. (Refer to 7 - COOLING/
ACCESSORY DRIVE/DRIVE BELTS - 2.4L -
REMOVAL) or (Refer to 7 - COOLING/ACCESSORY
DRIVE/DRIVE BELTS - 3.3L/3.8L - REMOVAL).
(13) Disconnect the engine wire harness connector
for the compressor clutch coil from the coil pigtail
wire connector on the top of the compressor (Fig. 1)
or (Fig. 2).
(14) On models with the 3.3L and 3.8L engines,
disengage the retainer on the engine wire harness
compressor clutch coil take out from the bracket on
the top of the compressor.
(15) On models with the 2.4L engine, remove the
four screws that secure the compressor to the mount-
ing bracket on the engine.
(16) On models with the 3.3L and 3.8L engines,
remove the three screws and one nut that secure the
compressor to the engine.
(17) Remove the compressor from the engine com-
partment.
NOTE: If a replacement compressor is being
installed, be certain to drain and measure the refrig-
erant oil contained in the removed compressor.
This will determine how much oil the replacement
compressor must contain before it is installed.(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - FRONT/REFRIGERANT OIL - STAN-
DARD PROCEDURE - REFRIGERANT OIL LEVEL).
REMOVAL - COMPRESSOR MOUNTING
BRACKET - 2.4L ENGINE
(1) Remove the compressor from the mounting
bracket. (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING/COMPRESSOR - REMOVAL).
(2) Remove the four screws that secure the com-
pressor mounting bracket to the engine (Fig. 3).
(3) Remove the compressor mounting bracket from
the engine.
INSTALLATION - COMPRESSOR
NOTE: If a replacement compressor is being
installed, be certain to check the refrigerant oil
level. (Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - FRONT/REFRIGERANT OIL - STAN-
DARD PROCEDURE - REFRIGERANT OIL LEVEL).
Use only refrigerant oil of the type recommended
for the compressor in the vehicle.
(1) Position the compressor into the engine com-
partment.
(2) On models with the 2.4L engine, loosely install
the four screws that secure the compressor to the
mounting bracket on the engine (Fig. 1). Tighten the
screws to 28 N´m (21 ft. lbs.).
Fig. 1 Compressor - 2.4L Engine
1 - CLUTCH COIL CONNECTOR
2 - DISCHARGE PORT
3 - COMPRESSOR
4 - SUCTION PORT
5 - SCREW (4)
6 - COMPRESSOR MOUNTING BRACKET
Fig. 2 Compressor - 3.3L/3.8L Engine
1 - STUD
2 - CLUTCH COIL CONNECTOR
3 - DISCHARGE PORT
4 - SCREW (2)
5 - SUCTION PORT
6 - COMPRESSOR
7 - SCREW
8 - NUT
24 - 66 PLUMBING - FRONTRS
COMPRESSOR (Continued)
ProCarManuals.com
(3) On models with the 3.3L and 3.8L engines,
loosely install the three screws and one nut that
secure the compressor to the engine (Fig. 2). Tighten
each of the fasteners using the following sequence to
54 N´m (40 ft. lbs.).
²The upper screw at the rear of the compressor.
²The lower screw at the rear of the compressor.
²The lower screw at the front of the compressor.
²The upper nut at the front of the compressor.
(4) On models with the 3.3L and 3.8L engines only,
engage the retainer on the engine wire harness com-
pressor clutch coil take out with the bracket on the
top of the compressor.
(5) Reconnect the engine wire harness connector
for the compressor clutch coil to the coil pigtail wire
connector on the top of the compressor.
(6) Reinstall the serpentine accessory drive belt
onto the front of the engine. (Refer to 7 - COOLING/
ACCESSORY DRIVE/DRIVE BELTS - 2.4L -
INSTALLATION) or (Refer to 7 - COOLING/ACCES-
SORY DRIVE/DRIVE BELTS - 3.3L/3.8L - INSTAL-
LATION).
(7) Lower the vehicle.
(8) Remove the tape or plugs from the compressor
discharge port and the discharge line fitting.
(9) Lubricate a new rubber O-ring seal with clean
refrigerant oil and install it on the discharge line fit-
ting.
(10) Reconnect the discharge line fitting to the
compressor discharge port.
(11) Install and tighten the nut that secures the
discharge line fitting to the compressor. Tighten the
nut to 23 N´m (17 ft. lbs.).
(12) Remove the tape or plugs from the compressor
suction port and the suction line fitting.(13) Lubricate a new rubber O-ring seal with clean
refrigerant oil and install it on the suction line fit-
ting.
(14) Reconnect the suction line fitting to the com-
pressor suction port.
(15) Install and tighten the nut that secures the
suction line fitting to the compressor. Tighten the nut
to 23 N´m (17 ft. lbs.).
(16) Reconnect the battery negative cable.
(17) Evacuate the refrigerant system. (Refer to 24
- HEATING & AIR CONDITIONING/PLUMBING -
FRONT/REFRIGERANT - STANDARD PROCE-
DURE - REFRIGERANT SYSTEM EVACUATE).
(18) Charge the refrigerant system. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
FRONT/REFRIGERANT - STANDARD PROCE-
DURE - REFRIGERANT SYSTEM CHARGE).
INSTALLATION - COMPRESSOR MOUNTING
BRACKET - 2.4L ENGINE
(1) Position the compressor mounting bracket onto
the engine (Fig. 3).
(2) Install and tighten the four screws that secure
the compressor mounting bracket to the engine.
Tighten the screws to 54 N´m (40 ft. lbs.).
(3) Reinstall the compressor onto the mounting
bracket. (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING/COMPRESSOR - INSTALLA-
TION).
CONDENSER
DESCRIPTION
The condenser is integral to a cooling module
which includes the radiator, the electric cooling fan,
the fan shroud, air seals and an automatic transmis-
sion oil cooler. The cooling module is located in the
air flow in the front of the engine compartment
behind the radiator grille. The condenser cannot be
repaired or adjusted and, if faulty or damaged, it
must be replaced. The condenser may be removed
from the cooling module for service without removing
the cooling module from the vehicle.
OPERATION
The condenser is a heat exchanger that allows the
high-pressure refrigerant gas being discharged by the
compressor to give up its heat to the air passing over
the condenser fins. When the refrigerant gas gives up
its heat, it condenses. When the refrigerant leaves
the condenser, it has become a high-pressure liquid
refrigerant. The volume of air flowing over the con-
denser fins is critical to the proper cooling perfor-
mance of the air conditioning system. Therefore, it is
important that there are no objects placed in front of
Fig. 3 Compressor Mounting Bracket - 2.4L Engine
1 - MOUNTING BRACKET
2 - SCREWS (4)
3 - ENGINE
RSPLUMBING - FRONT24-67
COMPRESSOR (Continued)
ProCarManuals.com
the radiator grille openings in the front of the vehicle
or foreign material on the condenser fins that might
obstruct air flow. Also, any factory-installed air seals
or shrouds must be properly reinstalled following
radiator or condenser service.
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).
NOTE: Before removing the condenser, note the
location of each of the radiator and condenser air
seals. These air seals are used to direct air through
the condenser and radiator. The air seals must be
reinstalled in their proper locations in order for the
air conditioning and engine cooling systems to per-
form as designed.
(1) Recover the refrigerant from the refrigerant
system. (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING - FRONT/REFRIGERANT -
STANDARD PROCEDURE - REFRIGERANT
RECOVERY).
(2) Remove the two large screws that secure the
front fascia and the outboard ends of the radiator
sight shield to the radiator closure panel crossmem-
ber (Fig. 4).(3) Remove the five small screws that secure the
front fascia grille inserts to the radiator sight shield.
(4) Remove the radiator sight shield from the radi-
ator closure panel crossmember.
(5) Remove the two screws that secure the hood
latch unit to the front of the radiator closure panel
crossmember and move the latch out of the way over
the top of the crossmember. Mark the location of
latch for reinstallation.
(6) Disconnect the hoses from the transmission oil
cooler fittings on the left side of the cooling module.
(Refer to 7 - COOLING/TRANSMISSION/TRANS
COOLER LINES - REMOVAL).
(7) Remove the nut that secures the discharge line
fitting to the condenser on the right side of the cool-
ing module.
(8) Disconnect the discharge line fitting from the
condenser inlet port.
(9) Remove the seal from the discharge line fitting
and discard.
(10) Install plugs in, or tape over the opened dis-
charge line fitting and the condenser inlet port.
(11) Remove the nut that secures the liquid line
fitting to the condenser on the right side of the cool-
ing module.
(12) Disconnect the liquid line fitting from the con-
denser outlet port.
(13) Remove the seal from the liquid line fitting
and discard.
(14) Install plugs in, or tape over the opened liquid
line fitting and the condenser outlet port.
(15) Remove the screw that secures the top of the
mounting bracket on each side of the condenser to
the cooling module (Fig. 5).
(16) Lift the condenser, transmission oil cooler, and
mounting brackets as a unit far enough to disengage
the locating pin that secures the mounting brackets
in the lower mount rubber isolators on each side of
the cooling module.
(17) Remove the condenser, transmission oil cooler,
and mounting brackets from the vehicle as a unit.
(18) Remove the two screws that secure each
mounting bracket to the sides of the condenser.
(19) Remove the one screw that secures the left
mounting bracket to the side of the transmission oil
cooler.
(20) Remove the left mounting bracket from the
side of the condenser and transmission oil cooler.
(21) Remove the condenser from the right mount-
ing bracket and transmission oil cooler unit.
Fig. 4 Radiator Sight Shield
1 - LARGE SCREWS (2)
2 - SMALL SCREWS (5)
3 - RADIATOR SIGHT SHIELD
4 - GRILLE INSERTS
5 - FRONT FASCIA
24 - 68 PLUMBING - FRONTRS
CONDENSER (Continued)
ProCarManuals.com
INSTALLATION
NOTE: If the condenser is being replaced, add 30
milliliters (1 fluid ounce) of refrigerant oil to the
refrigerant system. Use only refrigerant oil of the
type recommended for the compressor in the vehi-
cle.
NOTE: Be certain that each of the radiator and con-
denser air seals are reinstalled in their proper loca-
tions. These air seals are required in order for the
air conditioning and engine cooling systems to per-
form as designed.
(1) Position the condenser to the right mounting
bracket and transmission oil cooler unit.
(2) Position the left mounting bracket onto the side
of the condenser and transmission oil cooler.
(3) Install and tighten the one screw that secures
the left mounting bracket to the side of the transmis-
sion oil cooler. Tighten the screw to 5 N´m (45 in.
lbs.).
(4) Install and tighten the two screws that secure
each mounting bracket to the sides of the condenser.
Tighten the screws to 5 N´m (45 in. lbs.).(5) Position the condenser, transmission oil cooler,
and mounting brackets into the vehicle as a unit. Be
certain that the locating pins that secure the mount-
ing brackets are engaged in the lower mount rubber
isolators on each side of the cooling module (Fig. 5).
(6) Install and tighten the two screws that secure
the top of the mounting bracket on each side of the
condenser to the cooling module. Tighten the screws
to 5 N´m (45 in. lbs.).
(7) Remove the tape or plugs from the condenser
outlet port and the liquid line fitting.
(8) Lubricate a new rubber O-ring seal with clean
refrigerant oil and install it on the liquid line fitting.
(9) Reconnect the liquid line fitting to the con-
denser outlet port on the right side of the cooling
module.
(10) Install and tighten the nut that secures the
liquid line fitting to the condenser. Tighten the nut to
23 N´m (17 ft. lbs.).
(11) Remove the tape or plugs from the condenser
inlet port and the discharge line fitting.
(12) Lubricate a new rubber O-ring seal with clean
refrigerant oil and install it on the discharge line fit-
ting.
(13) Reconnect the discharge line fitting to the
condenser inlet port on the right side of the cooling
module.
(14) Install and tighten the nut that secures the
discharge line fitting to the condenser. Tighten the
nut to 23 N´m (17 ft. lbs.).
(15) Reconnect the hoses to the transmission oil
cooler fittings on the left side of the cooling module.
(Refer to 7 - COOLING/TRANSMISSION/TRANS
COOLER LINES - INSTALLATION).
(16) Reposition the hood latch unit to the front of
the radiator closure panel crossmember.
(17) Install and tighten the two screws that secure
the hood latch unit to the front of the radiator clo-
sure panel crossmember. Check and adjust the hood
latch as needed. Tighten the screws to 14 N´m (123
in. lbs.).
(18) Position the radiator sight shield onto the
radiator closure panel crossmember (Fig. 4).
(19) Install and tighten the five small screws that
secure the front fascia grille inserts to the radiator
sight shield. Tighten the screws to 2 N´m (18 in. lbs.).
(20) Install and tighten the two large screws that
secure the front fascia and the outboard ends of the
radiator sight shield to the radiator closure panel
crossmember. Tighten the screws to 6 N´m (53 in.
lbs.).
(21) Evacuate the refrigerant system. (Refer to 24
- HEATING & AIR CONDITIONING/PLUMBING -
FRONT/REFRIGERANT - STANDARD PROCE-
DURE - REFRIGERANT SYSTEM EVACUATE).
Fig. 5 Condenser Mounting
1 - SCREW (2)
2 - LOWER MOUNT ISOLATOR (2)
3 - CONDENSER
RSPLUMBING - FRONT24-69
CONDENSER (Continued)
ProCarManuals.com
(22) Charge the refrigerant system. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
FRONT/REFRIGERANT - STANDARD PROCE-
DURE - REFRIGERANT SYSTEM CHARGE).
DISCHARGE LINE
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 CONDI-
TIONING/PLUMBING - FRONT/REFRIGERANT -
STANDARD PROCEDURE - REFRIGERANT
RECOVERY).
(2) Remove the two large screws that secure the
front fascia and the outboard ends of the radiator
sight shield to the radiator closure panel crossmem-
ber (Fig. 6).
(3) Remove the five small screws that secure the
front fascia grille inserts to the radiator sight shield.
(4) Remove the radiator sight shield from the radi-
ator closure panel crossmember.(5) Remove the nut that secures the discharge line
fitting to the condenser on the right side of the cool-
ing module (Fig. 7).
(6) Disconnect the discharge line fitting from the
condenser inlet port.
(7) Remove the seal from the discharge line fitting
and discard.
(8) Install plugs in, or tape over the opened dis-
charge line fitting and the condenser inlet port.
(9) Remove the nut that secures the discharge line
fitting to the top of the compressor (Fig. 8).
(10) Disconnect the discharge line fitting from the
compressor discharge port.
(11) Remove the seal from the discharge line fit-
ting and discard.
(12) Install plugs in, or tape over the opened dis-
charge line fitting and the compressor discharge port.
(13) Remove the discharge line from the engine
compartment.
INSTALLATION
(1) Position the discharge line into the engine com-
partment.
(2) Remove the tape or plugs from the compressor
discharge port and the discharge line fitting (Fig. 8).
(3) Lubricate a new rubber O-ring seal with clean
refrigerant oil and install it on the discharge line fit-
ting.
(4) Reconnect the discharge line fitting to the com-
pressor discharge port on the top of the compressor.
(5) Install and tighten the nut that secures the
discharge line fitting to the compressor. Tighten the
nut to 23 N´m (17 ft. lbs.).Fig. 6 Radiator Sight Shield
1 - LARGE SCREWS (2)
2 - SMALL SCREWS (5)
3 - RADIATOR SIGHT SHIELD
4 - GRILLE INSERTS
5 - FRONT FASCIA
Fig. 7 Condenser Connections
1 - CONDENSER
2 - DISCHARGE LINE FITTING
3 - LIQUID LINE FITTING
4 - NUT
24 - 70 PLUMBING - FRONTRS
CONDENSER (Continued)
ProCarManuals.com
(6) Remove the tape or plugs from the condenser
inlet port and the discharge line fitting (Fig. 7).
(7) Lubricate a new rubber O-ring seal with clean
refrigerant oil and install it on the discharge line fit-
ting.
(8) Reconnect the discharge line fitting to the con-
denser inlet port on the right side of the cooling mod-
ule.
(9) Install and tighten the nut that secures the
discharge line fitting to the condenser. Tighten the
nut to 23 N´m (17 ft. lbs.).
(10) Position the radiator sight shield onto the
radiator closure panel crossmember (Fig. 6).
(11) Install and tighten the five small screws that
secure the front fascia grille inserts to the radiator
sight shield. Tighten the screws to 2 N´m (18 in. lbs.).
(12) Install and tighten the two large screws that
secure the front fascia and the outboard ends of the
radiator sight shield to the radiator closure panel
crossmember. Tighten the screws to 6 N´m (53 in.
lbs.).
(13) Evacuate the refrigerant system. (Refer to 24
- HEATING & AIR CONDITIONING/PLUMBING -
FRONT/REFRIGERANT - STANDARD PROCE-
DURE - REFRIGERANT SYSTEM EVACUATE).
(14) Charge the refrigerant system. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
FRONT/REFRIGERANT - STANDARD PROCE-
DURE - REFRIGERANT SYSTEM CHARGE).
EVAPORATOR
DESCRIPTION
The evaporator is located in the heater-A/C unit
housing, behind the instrument panel. The evapora-
tor is positioned in the heater-A/C housing so that all
air that enters the housing must pass over the fins of
the evaporator before it is distributed through the
system ducts and outlets. However, air passing over
the evaporator fins will only be conditioned when the
compressor is engaged and circulating refrigerant
through the evaporator tubes. The heater-A/C unit
housing must be removed from the vehicle to access
the evaporator for service. The evaporator cannot be
adjusted or repaired and, if faulty or damaged, it
must be replaced.
OPERATION
Refrigerant enters the evaporator from the expan-
sion valve as a low-temperature, low-pressure liquid.
As air flows over the fins of the evaporator, the
humidity in the air condenses on the fins, and the
heat from the air is absorbed by the refrigerant. Heat
absorption causes the refrigerant to boil and vapor-
ize. The refrigerant becomes a low-pressure gas when
it leaves the evaporator.
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),
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - FRONT - CAUTION - A/C PLUMBING),
and (Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - FRONT - WARNING - HEATER PLUMB-
ING).
(1) Remove the HVAC unit housing from the vehi-
cle. (Refer to 24 - HEATING & AIR CONDITION-
ING/DISTRIBUTION - FRONT/HVAC HOUSING -
REMOVAL).
(2) Remove the heater core tubes from the heater
core. (Refer to 24 - HEATING & AIR CONDITION-
ING/PLUMBING - FRONT/HEATER CORE -
REMOVAL - HEATER CORE TUBES).
(3) Remove and discard the foam seal from the
HVAC housing seal flange around the fresh air inlet
opening and the expansion valve/evaporator tube
opening on the dash panel side of the unit.
(4) Remove the expansion valve from the evapora-
tor inlet and outlet tube fittings. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
FRONT/EXPANSION VALVE - REMOVAL).
Fig. 8 Discharge Line
1 - DISCHARGE LINE
2 - NUT
3 - DISCHARGE LINE FITTING
4 - STUD
5 - DISCHARGE PORT
RSPLUMBING - FRONT24-71
DISCHARGE LINE (Continued)
ProCarManuals.com
(14) Reinstall the expansion valve onto the evapo-
rator inlet and outlet tube fittings. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
FRONT/EXPANSION VALVE - INSTALLATION).
(15) Install a new foam seal onto the HVAC hous-
ing seal flange around the fresh air inlet opening and
the expansion valve/evaporator tube opening on the
dash panel side of the unit.
(16) Reinstall the heater core tubes into the heater
core. (Refer to 24 - HEATING & AIR CONDITION-
ING/PLUMBING - FRONT/HEATER CORE -
INSTALLATION - HEATER CORE TUBES).
(17) Reinstall the HVAC unit housing into the
vehicle. (Refer to 24 - HEATING & AIR CONDI-
TIONING/DISTRIBUTION - FRONT/HVAC HOUS-
ING - INSTALLATION).
EXPANSION VALVE
DESCRIPTION
The front ªHº valve-type thermal expansion valve
(TXV) is located at the dash panel between the liquid
and suction lines, and the evaporator coil. The
assembly consists of an H-valve body and a thermal
sensor. High-pressure, low temperature liquid refrig-
erant from the liquid line passes through the expan-
sion valve orifice, converting it into a low-pressure,
low-temperature mixture of liquid and gas before it
enters the evaporator coil. The expansion valve is a
factory calibrated unit and cannot be adjusted or
repaired. If faulty or damaged, the expansion valve
must be replaced.
OPERATION
A mechanical sensor in the expansion valve control
head monitors the temperature and pressure of the
refrigerant leaving the evaporator coil through the
suction line, and adjusts the orifice size at the liquid
line to let the proper amount of refrigerant into the
evaporator coil to meet the vehicle cooling require-
ments. Controlling the refrigerant flow through the
evaporator ensures that none of the refrigerant leav-
ing the evaporator is still in a liquid state, which
could damage the compressor. The thermo sensor
measures refrigerant liquid temperature which is
monitored by the a/c control assembly.
DIAGNOSIS AND TESTING - EXPANSION VALVE
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).
NOTE: The expansion valve should only be tested
following testing of the compressor.
NOTE: Liquid CO
2is required to test the expansion
valve. This material is available from most welding
supply facilities. Liquid CO
2is also available from
companies which service and sell fire extinguish-
ers.
When testing the expansion valve, the work area
and the vehicle temperature must be 21É to 27É C
(70É to 85É F). To test the expansion valve:
(1) Connect a charging station or manifold gauge
set to the refrigerant system service ports. Verify the
refrigerant charge level.
(2) Close all doors, windows and vents to the pas-
senger compartment.
(3) Set the heater-air conditioner controls so that
the compressor is operating, the temperature control
is in the highest temperature position, the mode door
is directing the output to the floor outlets, and the
blower is operating at the highest speed setting.
(4) Start the engine and allow it to idle at 1000
rpm. After the engine has reached normal operating
temperature, allow the passenger compartment to
heat up. This will create the need for maximum
refrigerant flow into the evaporator.
(5) If the refrigerant charge is sufficient, the dis-
charge (high pressure) gauge should read 965 to 1655
kPa (140 to 240 psi). The suction (low pressure)
gauge should read 140 kPa to 207 kPa (20 psi to 30
psi). If OK, go to Step 6. If not OK, replace the faulty
expansion valve.
WARNING:
PROTECT THE SKIN AND EYES FROM EXPOSURE
TO LIQUID CO
2. PERSONAL INJURY CAN RESULT.
(6) If the suction (low pressure) gauge reads
within the specified range, freeze the expansion valve
control head for 30 seconds using liquid CO
2or
another suitable super-cold material.Do not spray
R-134a or R-12 refrigerant on the expansion
valve control head for this test.The suction (low
pressure) gauge reading should drop by 10 psi. If OK,
go to Step 7 If not OK, replace the faulty expansion
valve.
(7) Allow the expansion valve control head to thaw.
The suction (low pressure) gauge reading should sta-
bilize at 140 kPa to 240 kPa (20 psi to 30 psi). If not
OK, replace the faulty expansion valve.
(8) When expansion valve testing is complete, test
the overall air conditioner performance. (Refer to 24 -
24 - 74 PLUMBING - FRONTRS
EVAPORATOR (Continued)
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