Content .. 2356 2357 2358 2359 ..

Chrysler 300/300 Touring/300C, Dodge Magnum. Manual - part 2358

VALVE-A/C EXPANSION

DESCRIPTION

The A/C expansion valve controls the amount of refrig-
erant entering the A/C evaporator and is of a thermo-
static

expansion

valve

(TXV)

design.

The

A/C

expansion valve consists of an aluminum H-valve type
body (1) with an integral thermal sensor (2) and is
located at the dash panel between the A/C refrigerant
lines and the A/C evaporator.

OPERATION

The A/C expansion valve controls the high-pressure, low temperature liquid refrigerant from the liquid line and con-
verts it into a low-pressure, low-temperature mixture of liquid and gas before it enters the A/C evaporator. A mechan-
ical sensor in the A/C expansion valve monitors the temperature and pressure of the refrigerant leaving the A/C
evaporator through the suction line, and adjusts the orifice size at the liquid line port to let the proper amount of
refrigerant into the A/C evaporator to meet the vehicle A/C cooling requirements. Controlling the refrigerant flow
through the A/C evaporator ensures that none of the refrigerant leaving the A/C evaporator is still in a liquid state,
which could damage the A/C compressor.

The A/C expansion valve is factory calibrated and cannot be adjusted or repaired and, if faulty or damaged, it must
be replaced.

DIAGNOSIS AND TESTING

A/C EXPANSION VALVE

WARNING: Refer to the applicable warnings and cautions for this system before performing the following
operation (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - WARNINGS) and (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING - CAUTIONS). Failure to follow the warnings and cautions could result
in possible personal injury or death.

NOTE: The A/C expansion valve should only be tested following testing of the A/C compressor.

NOTE: Liquid CO

is required to test the A/C expansion valve. This material is available from most welding

supply facilities. Liquid CO

is also available from companies which service and sell fire extinguishers.

When testing the A/C expansion valve, the work area and the vehicle temperature must be 21° to 27° C (70° to 85°
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 passenger compartment.

3. Set the A/C-heater controls so that the A/C compressor is operating, the temperature control is in the highest

temperature position, the mode-air doors is directing air output to the floor and the blower motor operating is
operating at the highest speed.

24 - 466

PLUMBING

4. Start the engine and allow it to idle. After the engine has reached normal operating temperature, allow the pas-

senger compartment to heat up. This will create the need for maximum refrigerant flow into the A/C evaporator.

5. If the refrigerant charge is sufficient, the discharge (high pressure) gauge should read 827 kPa to 1655 kPa (120

psi to 240 psi). The suction (low pressure) gauge should read 207 kPa to 345 kPa (30 psi to 50 psi). If OK, go
to Step 6. If not OK, replace the faulty A/C expansion valve.

WARNING:
Protect the skin and eyes from exposure to liquid CO

or personal injury can result.

6. If the suction (low pressure) gauge reads within the specified range, freeze the A/C expansion valve for 30 sec-

onds using liquid CO

or another suitable super-cold material.Do not spray R-134a or R-12 refrigerant on the

A/C expansion valve for this test. The suction (low pressure) gauge reading should drop by 69 kPa (10 psi).
If OK, go to Step 7 If not OK, replace the faulty A/C expansion valve.

7. Allow the expansion valve control head to thaw. The suction (low pressure) gauge reading should stabilize at 207

kPa to 345 kPa (30 psi to 50 psi). If not OK, replace the faulty A/C expansion valve.

8. When expansion valve testing is complete, test the overall A/C system performance (Refer to 24 - HEATING &

AIR CONDITIONING - DIAGNOSIS AND TESTING - A/C PERFORMANCE TEST).

REMOVAL

NOTE: LHD model shown in illustrations. RHD model similar.

1. Recover the refrigerant from the refrigerant system

(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING

STANDARD

PROCEDURE

REFRIGERANT SYSTEM RECOVERY).

2. Disconnect and isolate the negative battery cable.

3. Remove the bolt (5) that secures the refrigerant

line mounting bracket (6) to the left front shock
tower (4).

4. Remove the nut (9) that secures the refrigerant line

tapping block (10) to the A/C expansion valve (1).

5. Disconnect the wire harness (3) from the A/C pres-

sure transducer (2) to help allow access to the A/C
expansion valve.

6. Disconnect the A/C suction line (7) and the A/C liq-

uid line (8) from the A/C expansion valve and posi-
tion the refrigerant lines out of the way.

7. Remove the dual plane seal from the suction and

liquid line fittings and discard.

8. Install plugs in, or tape over the opened suction and liquid line fittings.

PLUMBING

24 - 467

9. Remove the two bolts (1) that secure the A/C

expansion valve (2) to the evaporator tube tapping
block located within the foam seal (3).

10. Remove the A/C expansion valve from the evap-

orator tube tapping block and foam seal.

11. Remove the dual plane seal from the evaporator

tube fittings and discard.

12. Install plugs in, or tape over the opened evapora-

tor tube fittings and all expansion valve ports.

INSTALLATION

NOTE: LHD model shown in illustrations. RHD model similar.

1. Remove the tape or plugs from the evaporator tube

fittings and all of the expansion valve ports.

2. Lubricate a new dual plane seal with clean refrig-

erant oil and install it onto the evaporator tube fit-
tings. Use only the specified seal as it is made of a
special material for the R-134a system. Use only
refrigerant oil of the type recommended for the A/C
compressor in the vehicle.

3. Install the A/C expansion valve (2) onto the evapo-

rator tube tapping block located within the foam
seal (3).

4. Install the two bolts (1) that secure the A/C expan-

sion valve to the evaporator tube tapping block.
Tighten the bolts to 11 N·m (97 in. lbs.).

24 - 468

PLUMBING

5. Remove the tape or plugs from the suction and liq-

uid line fittings.

6. Lubricate a new dual plane seal with clean refrig-

erant oil and install it onto the suction and liquid
line fittings. Use only the specified seal as it is
made of a special material for the R-134a system.
Use only refrigerant oil of the type recommended
for the A/C compressor in the vehicle.

7. Connect the A/C suction line (7) and the A/C liquid

line (8) to the A/C expansion valve (1).

8. Install the nut (9) that secures the refrigerant line

tapping block (10) to the A/C expansion valve.
Tighten the nut to 23 N·m (17 ft. lbs.).

9. Install the bolt (5) that secures the refrigerant line

mounting bracket (6) to the left front shock tower
(4). Tighten the bolt to 11 N·m (97 in. lbs.).

10. Connect the wire harness (3) to the A/C pressure

transducer (2).

11. Reconnect the negative battery cable.

12. Evacuate the refrigerant system (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STANDARD

PROCEDURE - REFRIGERANT SYSTEM EVACUATE).

13. Recharge the refrigerant system (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STANDARD

PROCEDURE - REFRIGERANT SYSTEM CHARGE).

PLUMBING

24 - 469

Content .. 2356 2357 2358 2359 ..