internal pressure of 97 to 123 kPa (14 to 18 psi).
Wait 15 minutes (after the engine is shut off), or
until safe temperature and pressure is attained,
before opening the cooling system. Refer to Coolin-
g(Refer to 7 - COOLING - OPERATION). Coolant
temperature can be checked using the scan tool
(DRBIII

t).

When additional coolant is needed, it should be

added to the coolant pressure bottle. Use only 50/50
mix of Mopar

t Antifreeze/Coolant, 5 Year/100,000

Mile Formula (orange in color), or the equivalent and
distilled water. This coolant must not be mixed with

other (green in color) coolants. If this occurs, a reduc-
tion in the extended service interval will result. Refer
to Lubrication and Maintenance for service sched-
ules(Refer to LUBRICATION & MAINTENANCE -
SPECIFICATIONS).

CAUTION: Do not add additional inhibitors, anti-rust
products, or soluble oil (sold as “water pump lubri-
cants”). These products may not be compatible
with the engine coolant.

Refer to Cooling for cooling system procedures(Re-

fer to 7 - COOLING - STANDARD PROCEDURE).

DIAGNOSIS AND TESTING

DIAGNOSIS AND TESTING - A/C
PERFORMANCE TEST

The air conditioning system is designed to remove

heat and humidity from the air entering the passen-
ger compartment. The evaporator, located in the
HVAC unit, is cooled to temperatures near the freez-
ing point. As warm damp air passes over the fins in
the evaporator, moisture in the air condenses to
water, dehumidifying the air. High humidity reduces
the evaporator’s ability to cool the air. During periods
of high heat and humidity, an air conditioning sys-
tem will be less effective. With the a/c heater control
set to RECIRC, only air from the passenger compart-
ment passes through the evaporator. As the passen-
ger compartment air dehumidifies, A/C performance
levels rise.

HEATING & AIR CONDITIONING

24 - 1

PERFORMANCE TEST PROCEDURE

Before performing the following procedure, (Refer

to 24 - HEATING & AIR CONDITIONING/PLUMB-
ING - WARNING). Air temperature in test room and
in vehicle must be 21° C (70°F) minimum for this
test.

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 tachometer and manifold gauge set

or an A/C Charging/Recycling Station.

(2) Set controls:

MTC (Manual Temperature Control) System:

• A/C ON

• Panel Recirculation

• Temperature to full cold

• High blower

ATC (Automatic Temperature Control) System:

• Rotate blower knob to high position (full clock-

wise)

• Set temperature to the LO position

• Push panel mode button

• Push RECIRC (Recirculation) button (A/C and

RECIRC symbols should be lit)

NOTE: The word MANUAL should appear in the ATC
display, confirming that the system is set manually.

(3) Start engine and hold at 1000 rpm with A/C

clutch engaged.

(4) Engine should be warmed up with doors and

windows closed.

(5) Insert a thermometer in the left center A/C

outlet and operate the engine for five minutes. The
A/C clutch may cycle depending on ambient condi-
tions.

(6) With the A/C clutch engaged, compare the

discharge air temperature to the A/C Performance
Temperature table.

A/C PERFORMANCE TEMPERATURE AND PRESSURE

AMBIENT TEMPERATURE

21°C

(70°F)

26.5°C

(80°F)

32.5°C

(90°F)

37°C

(100°F)

43°C

(110°F)

MAXIMUM ALLOWABLE AIR
TEMPERATURE AT CENTER
LEFT PANEL OUTLET

6°C

(42°F)

7°C

(45°F)

10°C

(50°F)

12°C

(54°F)

15°C

(59°F)

COMPRESSOR DISCHARGE
PRESSURE

1379–1585

kPa

(200–230

psi)

1448–1723

kPa

(210–250

psi)

1654–1930

kPa

(240–280

psi)

1930–2206

kPa

(280–320

psi)

2206–2516

kPa

(320–365 psi)

COMPRESSOR SUCTION
PRESSURE

103–172 kPa

(15–25 psi)

139–208 kPa

(20–30 psi)

172–241 kPa

(25–35 psi)

208–276 kPa

(30–40 psi)

241–310 kPa

(35–45 psi)

DIAGNOSIS AND TESTING - HEATER
PERFORMANCE TEST

PRE-DIAGNOSTIC PREPARATIONS

Check the coolant level, drive belt tension, vacuum

line connections, electrical connections, radiator air
flow and fan operation. Start engine and allow to
warm up to normal temperature.

WARNING:

NOT

REMOVE

RADIATOR

CAP

WHEN

ENGINE

HOT,

SEVERE

PERSONAL

INJURY CAN RESULT.

If vehicle has been run recently, wait until engine

is cool before removing cap. Squeeze the radiator

hose to check temperature, and for pressure in the
system. If the hose is very firm, allow time to cool
down. Place a rag over the cap and turn it to the first
safety stop. Allow pressure to escape through the
overflow tube. When the system stabilizes, remove
the cap completely.

MAXIMUM HEATER OUTPUT: TEST AND ACTION

Engine coolant is provided to the heater system by

two 19 mm (3/4 inch inside diameter) heater hoses.
With engine idling at normal running temperature,
set the control to maximum heat, floor, and high
blower setting. Using a test thermometer, check the
air temperature coming from the floor outlets. Refer
to Temperature Reference Table.

24 - 2

HEATING & AIR CONDITIONING

HEATING & AIR CONDITIONING (Continued)

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