2003 CHRYSLER CARAVAN ABS

the heater-A/C unit housing is directed through the
heater core.
REMOVAL
REMOVAL- HEATER CORE EXTENSION TUBES
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 - HEATER PLUMB-
ING).
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Drain the engine cooling system. (Refer to 7 -
COOLING - STANDARD PROCEDURE - COOLING
SYSTEM DRAIN).
(2) Disconnect and isolate the battery negative
cable.
(3) Disconnect the heater hoses from the heater
hose tubes. (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING - FRONT/HEATER HOSE -
REMOVAL).
(4) Remove the silencer from beneath the driver
side end of the instrument panel. (Refer to 23 -
BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL SILENCER - REMOVAL).
(5) Remove the three screws that secure the heater
core shield to the left end of the HVAC distribution
housing (Fig. 15).
(6) Pull the heater core shield rearward far enough
to disengage the two location tabs that position the
front of the shield to the receptacles in the two lower
finger formations of the evaporator housing near the
dash panel.
(7) Remove the heater core shield from the distri-
bution housing.
(8) Take the proper precautions to protect the car-
peting below the heater core from spilled engine cool-ant and have absorbent toweling readily available to
clean up any spills.
(9) Remove the screw that secures the heater core
tube sealing plate to the heater core supply and
return ports (Fig. 16).
(10) Push both heater core tubes simultaneously
toward the dash panel far enough to disengage their
fittings from the heater core supply and return ports.
(11) Install plugs in, or tape over the opened
heater core tube fittings and both heater core ports.
Fig. 15 Heater Core Shield
1 - HEATER/ AIR CONDITIONER HOUSING
2 - HEATER CORE SHIELD
3 - DISTRIBUTION HOUSING
4 - SCREWS (3)
5 - LOCATION TABS (2)
Fig. 16 Heater Core Tubes
1 - SEAL
2 - HEATER CORE TUBES
3 - SCREW
4 - HEATER CORE
5 - DISTRIBUTION HOUSING
6 - SEALING PLATE
RSPLUMBING - FRONT24-75
HEATER CORE (Continued)
ProCarManuals.com

(12) Use absorbent toweling to mop up any engine
coolant spills from the preceding operation.
(13) Pull both heater core tubes simultaneously
slightly away from the distribution housing and rear-
ward far enough to disengage the engine compart-
ment ends of the tubes from the dash panel seal.
(14) Remove the heater core tubes and sealing
plate as a unit from beneath the instrument panel.
(15) Use absorbent toweling to clean up any
engine coolant spills from the preceding operation.
REMOVAL - HEATER CORE
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 - HEATER PLUMB-
ING).
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Drain the engine cooling system. (Refer to 7 -
COOLING - STANDARD PROCEDURE - COOLING
SYSTEM DRAIN).
(2) Disconnect and isolate the battery negative
cable.
(3) Remove the silencer boot fasteners located
around the base of the lower steering shaft from the
dash panel so that it may be pushed aside.
(4) Remove the brake lamp switch from its mount-
ing bracket. (Refer to 8 - ELECTRICAL/LAMPS/
LIGHTING - EXTERIOR/BRAKE LAMP SWITCH -
REMOVAL).
(5) Disconnect the power brake booster input rod
(push rod) from the pin on the brake pedal arm.
(Refer to 5 - BRAKES - ABS/HYDRAULIC/ME-
CHANICAL/POWER BRAKE BOOSTER - REMOV-
AL).
(6) Remove the three screws that secure the heater
core shield to the left end of the HVAC distribution
housing (Fig. 17).(7) Pull the heater core shield rearward far enough
to disengage the two location tabs that position the
front of the shield to the receptacles in the two lower
finger formations of the evaporator housing near the
dash panel.
(8) Remove the heater core shield from the distri-
bution housing.
(9) Take the proper precautions to protect the car-
peting below the heater core from spilled engine cool-
ant and have absorbent toweling readily available to
mop up any spills.
(10) Remove the screw that secures the heater core
tube sealing plate to the heater core supply and
return ports (Fig. 18).
(11) Push both heater core tubes simultaneously
toward the dash panel far enough to disengage their
fittings from the heater core supply and return ports.
(12) Install plugs in, or tape over the opened
heater core tube fittings and both heater core ports.
(13) Use absorbent toweling to mop up any engine
coolant spills from the preceding operation.
(14) Remove the two screws that secure the heater
core mounting plate to the distribution housing.
(15) While pulling the accelerator pedal upward
(Fig. 19) and pushing the brake pedal downward
(Fig. 20) far enough for clearance, pull the heater
core out of the distribution housing.
(16) Use absorbent toweling to mop up any engine
coolant spills from the preceding operation. Also, if
the heater core was leaking, use absorbent toweling
and reach into the heater core opening to mop up
any residual engine coolant within the distribution
housing.
Fig. 17 Heater Core Shield
1 - HEATER/ AIR CONDITIONER HOUSING
2 - HEATER CORE SHIELD
3 - DISTRIBUTION HOUSING
4 - SCREWS (3)
5 - LOCATION TABS (2)
24 - 76 PLUMBING - FRONTRS
HEATER CORE (Continued)
ProCarManuals.com

INSTALLATION
INSTALLATION- HEATER CORE EXTENSION
TUBES
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 - HEATER PLUMB-
ING).
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFOREATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Remove the plugs or tape from both heater core
tube fittings and both heater core ports.
(2) Position the heater core tubes and sealing plate
as a unit beneath the instrument panel.
(3) Align the engine compartment ends of both
heater core tubes with the openings in the dash
panel seal and push them simultaneously forward
through the seal far enough to engage the heater
core ends of the tubes with the heater core supply
and return ports.
(4) Position both heater core tubes and the sealing
plate simultaneously to the heater core supply and
return ports.
(5) The heater core tubes each have a slot that
must be indexed to a location tab within each of the
heater core ports. Adjust the position of the tubes as
required so that the sealing plate fits flush against
the heater core supply and return ports, which indi-
cates that the tubes are properly indexed.
(6) Install and tighten the screw that secures the
heater core tube sealing plate to the heater core sup-
ply and return ports. Tighten the screw to 3 N´m (27
in. lbs.).
(7) Position the heater core shield onto the distri-
bution housing. Be certain that the two location tabs
Fig. 18 Heater Core
1 - SEALING PLATE
2 - SCREW
3 - SCREWS (2)
4 - HEATER CORE
5 - HEATER CORE TUBES
Fig. 19 Accelerator Pedal
1 - SLIDE HEATER CORE PAST ACCELERATOR PEDAL
Fig. 20 Brake Pedal
1 - SLIDE HEATER CORE PAST BRAKE PEDAL
2 - DEPRESS BRAKE PEDAL
RSPLUMBING - FRONT24-77
HEATER CORE (Continued)
ProCarManuals.com

on the front of the shield are engaged in the recepta-
cles in the two lower finger formations of the evapo-
rator housing near the dash panel.
(8) Install and tighten the three screws that secure
the heater core shield to the left end of the HVAC
distribution housing. Tighten the screws to 2 N´m (17
in. lbs.).
(9) Reinstall the silencer under the driver side end
of the instrument panel. (Refer to 23 - BODY/IN-
STRUMENT PANEL/INSTRUMENT PANEL
SILENCER - INSTALLATION).
(10) Reconnect the heater hoses to the heater hose
tubes. (Refer to 24 - HEATING & AIR CONDITION-
ING/PLUMBING - FRONT/HEATER HOSE -
INSTALLATION).
(11) Reconnect the battery negative cable.
(12) Refill the engine cooling system. (Refer to 7 -
COOLING - STANDARD PROCEDURE - COOLING
SYSTEM REFILL).
INSTALLATION - HEATER CORE
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 - HEATER PLUMB-
ING).
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) While pushing the brake pedal downward and
pulling the accelerator pedal upward far enough for
clearance, slide the heater core into the distribution
housing.
(2) Install and tighten the two screws that secure
the heater core mounting plate to the distribution
housing. Tighten the screws to 2 N´m (17 in. lbs.).
(3) Remove the plugs or tape from the heater core
tube fittings and both heater core ports.
(4) Position both heater core tubes and the sealing
plate simultaneously to the heater core supply and
return ports.(5) The heater core tubes each have a slot that
must be indexed to a location tab within each of the
heater core ports. Adjust the position of the tubes as
required so that the sealing plate fits flush against
the heater core supply and return ports, which indi-
cates that the tubes are properly indexed.
(6) Install and tighten the screw that secures the
heater core tube sealing plate to the heater core sup-
ply and return ports. Tighten the screw to 3 N´m (27
in. lbs.).
(7) Position the heater core shield onto the distri-
bution housing. Be certain that the two location tabs
on the front of the shield are engaged in the recepta-
cles in the two lower finger formations of the evapo-
rator housing near the dash panel.
(8) Install and tighten the three screws that secure
the heater core shield to the left end of the HVAC
distribution housing. Tighten the screws to 2 N´m (17
in. lbs.).
(9) Reconnect the power brake booster input rod
(push rod) to the pin on the brake pedal arm(Refer to
5 - BRAKES/HYDRAULIC/MECHANICAL/POWER
BRAKE BOOSTER - INSTALLATION).
(10) Reinstall the brake lamp switch into its
mounting bracket(Refer to 8 - ELECTRICAL/LAMPS/
LIGHTING - EXTERIOR/BRAKE LAMP SWITCH -
INSTALLATION).
(11) Reinstall the silencer boot around the base of
the lower steering shaft on the dash panel.
(12) Reconnect the battery negative cable.
(13) Refill the engine cooling system. (Refer to 7 -
COOLING - STANDARD PROCEDURE - COOLING
SYSTEM REFILL).
(14) Operate system for two thermostat cycles to
assure elimination of air in the system.
HEATER HOSE
REMOVAL
There are several heater core plumbing configura-
tions used on this model, depending upon the engine
size and other optional equipment. One plumbing
configuration is used for all 2.4L engines (Fig. 21),
while the 3.3L and 3.8L engines have unique heater
return plumbing on the engine for models with or
without an optional engine oil cooler (Fig. 24) or (Fig.
25). There are also unique plumbing configurations
at the heater core for models with or without the
optional rear heater and air conditioner (Fig. 22) or
(Fig. 23). All models use a combination of formed
steel tubing and rubber hoses. In most cases, the
rubber hose is secured to the steel tubing with a
spring tension clamp.
24 - 78 PLUMBING - FRONTRS
HEATER CORE (Continued)
ProCarManuals.com

indeterminable period or if the compressor has failed,
it must be replaced.
OPERATION
The filter-drier performs a filtering action to pre-
vent foreign material in the refrigerant from contam-
inating the expansion valve. A desiccant bag is
mounted inside the filter-drier canister to absorb any
moisture which may have entered and become
trapped within the refrigerant system. In addition,
during periods of high demand air conditioner opera-
tion, the filter-drier acts as a reservoir to store sur-
plus refrigerant. Refrigerant enters the filter-drier as
a high-pressure, low temperature liquid.
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 air cleaner housing from the right
side of the engine compartment.
(3) Remove the screw that secures the liquid line
front section fitting to the top of the filter-drier (Fig.
30).
(4) Disconnect the liquid line fitting from the fil-
ter-drier inlet port.
(5) Remove the seal from the liquid line fitting and
discard.
(6) Install plugs in, or tape over the opened liquid
line fitting and the filter-drier inlet port.
(7) Remove the screw that secures the liquid line
rear section fitting to the top of the filter-drier.
(8) Disconnect the liquid line fitting from the fil-
ter-drier outlet port.
(9) Remove the seal from the liquid line fitting and
discard.
(10) Install plugs in, or tape over the opened liquid
line fitting and the filter-drier outlet port.
(11) Remove the two nuts that secure the filter-
drier mounting bracket to the weld studs on the side
of the right front strut tower.
(12) Remove the filter-drier and mounting bracket
unit from the studs.
INSTALLATION
NOTE: If the filter-drier 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.
(1) Position the filter-drier and mounting bracket
unit onto the weld studs on the side of the right front
strut tower.
(2) Install and tighten the two nuts that secure
the filter-drier mounting bracket to the studs.
Tighten the nuts to 10 N´m (89 in. lbs.).
(3) Remove the tape or plugs from the liquid line
rear section fitting for the filter-drier and the filter-
drier outlet port.
(4) Lubricate a new rubber O-ring seal with clean
refrigerant oil and install it on the liquid line fitting.
(5) Reconnect the liquid line fitting to the filter-
drier outlet port on the top of the filter-drier.
Fig. 30 Front Liquid Lines
1 - A/C GROUND STRAP (IF EQUIPPED)
2 - NUT (IF EQUIPPED)
3 - WELD STUD (IF EQUIPPED)
4 - A/C PRESSURE TRANSDUCER
5 - WELD STUD (2)
6 - EXPANSION VALVE
7 - FRONT LIQUID LINE REAR SECTION
8 - LIQUID LINE EXTENSION (REAR A/C ONLY)
9 - NUT (2)
10 - FILTER-DRIER
11 - ROUTING CLIP
12 - FRONT LIQUID LINE FRONT SECTION
24 - 84 PLUMBING - FRONTRS
RECEIVER/DRIER (Continued)
ProCarManuals.com

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 10S20H com-
pressor used in this vehicle are 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).
When an air conditioning system is assembled at
the factory, all components except the compressor are
refrigerant oil free. After the refrigerant system has
been charged and operated, the refrigerant oil in the
compressor is dispersed throughout the refrigerant
system. The receiver/drier, evaporator, condenser, and
compressor will each retain a significant amount of
the needed refrigerant oil.
It is important to have the correct amount of oil in
the refrigerant system. This ensures proper lubrica-
tion of the compressor. Too little oil will result in
damage to the compressor. Too much oil will reduce
the cooling capacity of the air conditioning system.
It will not be necessary to check the oil level in the
compressor or to add oil, unless there has been an oil
loss. An oil loss may occur due to a rupture or leakfrom a refrigerant line, a connector fitting, a compo-
nent, or a component seal. If a leak occurs, add 30
milliliters (1 fluid ounce) of refrigerant oil to the
refrigerant system after the repair has been made.
Refrigerant oil loss will be evident at the leak point
by the presence of a wet, shiny surface around the
leak.
Refrigerant oil must be added when an receiver/
drier, evaporator or condenser is replaced. See the
Refrigerant Oil Capacities chart for the proper
amount of refrigerant oil to add. When a compressor
is replaced, the refrigerant oil must be drained from
the old compressor and measured. Drain all of the
refrigerant oil from the new compressor, then fill the
new compressor with the same amount of fresh new
refrigerant oil that was drained out of the old com-
pressor.
REFRIGERANT OIL CAPACITIES
Front A/C Front & Rear
A/C
COMPONENT ml fl oz ml fl oz
Total System Fill 140 5.0 180 6.43
Filter-Drier 25 0.9 25 0.9
Condenser 25 0.9 25 0.9
Front Evaporator 50 1.8 50 1.8
Rear Evap. (including
underbody lines)N/A N/A 50 1.8
Compressor Drain and measure the oil
from the old compressor -
See text above.
SUCTION LINE
REMOVAL
The front air conditioner suction line includes the
low side service port on a section of tubing located
near the compressor. On models equipped with the
optional rear air conditioner, the front air conditioner
suction line also includes a suction line hose and
tube extension that connects the front suction line to
the suction line for the rear air conditioner.
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-
24 - 90 PLUMBING - FRONTRS
ProCarManuals.com

PLUMBING - REAR
TABLE OF CONTENTS
page page
EVAPORATOR
DESCRIPTION.........................94
OPERATION...........................94
REMOVAL
REMOVAL - REAR EVAPORATOR.........94
REMOVAL - EVAPORATOR LINE
EXTENSION.........................95
INSTALLATION
INSTALLATION - REAR EVAPORATOR.....96
INSTALLATION - EVAPORATOR LINE
EXTENSION.........................96
EXPANSION VALVE
DESCRIPTION.........................96
OPERATION...........................97
DIAGNOSIS AND TESTING - EXPANSION
VALVE ..............................97
REMOVAL.............................97
INSTALLATION.........................98
HEATER CORE
DESCRIPTION.........................98
OPERATION...........................98STANDARD PROCEDURE - HEATER CORE
FILLING.............................98
REMOVAL.............................99
INSTALLATION........................100
HEATER HOSE
REMOVAL............................100
INSTALLATION........................101
SUCTION LINE
REMOVAL............................101
INSTALLATION........................102
UNDERBODY LINES
DESCRIPTION........................103
OPERATION..........................103
REMOVAL
REMOVAL - REAR HEATER LINES.......104
REMOVAL - REAR AIR CONDITIONING
LINES.............................104
INSTALLATION
INSTALLATION - REAR HEATER LINES....105
INSTALLATION - REAR AIR CONDITIONING
LINES.............................105
EVAPORATOR
DESCRIPTION
The rear evaporator is located in the rear heater-
A/C unit housing, behind the right rear wheel house.
The evaporator is positioned in the rear heater-A/C
housing so that all air that enters the housing must
pass over the fins of the evaporator before it is dis-
tributed through the system ducts and outlets. How-
ever, air passing over the evaporator fins will only be
conditioned when the compressor is engaged and cir-
culating refrigerant through the evaporator tubes.
The rear 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 rear evaporator from the
rear expansion valve as a low-temperature, low-pres-
sure liquid. As air flows over the fins of the evapora-
tor, the humidity in the air condenses on the fins,
and the heat from the air is absorbed by the refrig-
erant. Heat absorption causes the refrigerant to boil
and vaporize. The refrigerant becomes a low-pressure
gas when it leaves the evaporator.
REMOVAL
REMOVAL - REAR EVAPORATOR
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 rear heater-A/C unit housing from
the vehicle. (Refer to 24 - HEATING & AIR CONDI-
TIONING/DISTRIBUTION - REAR/REAR HEATER-
A/C HOUSING - REMOVAL).
(2) Remove the rear evaporator line extension from
the expansion valve. (Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING - REAR/EVAPORA-
TOR - REMOVAL - EVAPORATOR LINE EXTEN-
SION).
(3) Remove the rear expansion valve from the rear
evaporator. (Refer to 24 - HEATING & AIR CONDI-
24 - 94 PLUMBING - REARRS
ProCarManuals.com

INSTALLATION
(1) Remove the tape or plugs from the evaporator
tube fittings and both expansion valve ports.
(2) Lubricate new rubber O-ring seals with clean
refrigerant oil and install them on the evaporator
tube fittings.
(3) Position the expansion valve onto the evapora-
tor tubes.
(4) Install and tighten the two screws that secure
the expansion valve to the evaporator tube sealing
plate. Tighten the screws to 11 N´m (97 in. lbs.).
(5) Reinstall the rear evaporator line extension
onto the expansion valve. (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - REAR/EVAPO-
RATOR - INSTALLATION - EVAPORATOR LINE
EXTENSION).
(6) Install the foam insulator wrap over the rear
expansion valve.
(7) Reinstall the rear heater-A/C unit housing into
the vehicle. (Refer to 24 - HEATING & AIR CONDI-
TIONING/DISTRIBUTION - REAR/REAR HEATER-
A/C HOUSING - INSTALLATION).
(8) Run the HVAC Cooldown Test to verify proper
operation.
HEATER CORE
DESCRIPTION
The rear heater core is located near the front of
the rear heater-A/C unit housing, behind the right
rear wheel house. It is a heat exchanger made of
rows of tubes and fins. One end of the core is fitted
with a molded plastic tank that includes integral
heater core inlet and outlet nipples. The heater core
can be serviced without removing the rear heater-A/C
unit housing from the vehicle. The heater core cannot
be repaired and, if faulty or damaged, it must be
replaced.
OPERATION
Engine coolant is circulated through heater hoses
to the heater core at all times. As the coolant flows
through the heater core, heat removed from the
engine is transferred to the heater core fins and
tubes. Air directed through the heater core picks up
the heat from the heater core fins. The blend air door
allows control of the heater output air temperature
by controlling how much of the air flowing through
the rear heater-A/C unit housing is directed through
the heater core.
STANDARD PROCEDURE - HEATER CORE
FILLING
In its final installed position, the rear heater core
is positioned higher than the radiator fill cap. There-fore, when the cooling system is drained and refilled,
gravity will not refill the heater core with coolant to
the proper level. This may result in two problems:1.
Insufficient coolant level in the engine cooling sys-
tem, which may result in engine overheating.2.Air
entrapped within the rear heater core, which may
result in insufficient rear heater performance. There
are two methods that may be employed to prevent
these problems:1.Pre-filling of the rear heater core.
2.Thermal cycling of the engine cooling system. Fol-
lowing are descriptions of both prevention methods,
as well as a method to verify rear heater perfor-
mance.
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 - HEATER PLUMB-
ING).
PRE-FILLING
If the rear heater core or the rear heater-A/C hous-
ing have been removed from the vehicle for service,
the rear heater core may be pre-filled with the proper
engine coolant mixture prior to reconnecting the
heater hoses to the heater core hose fittings.
(1) The heater core should be installed in the rear
heater-A/C unit housing, and the rear heater-A/C
unit housing should be installed in the vehicle.
(2) Take the proper precautions to protect the car-
peting below the rear heater core from spilled engine
coolant and have absorbent toweling readily avail-
able to mop up any spills.
(3) Insert the small end of an appropriate funnel
into the upper hose fitting of the heater core (Fig. 4).
Fig. 4 Pre-Filling Heater Core - Typical
1 - REAR HEATER CORE
24 - 98 PLUMBING - REARRS
EXPANSION VALVE (Continued)
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