Dodge Neon / Neon SRT-4. Manual - part 433

REFRIGERANT SYSTEM CHARGE LEVEL

WARNING: Review safety precautions and warnings
in this group before performing this procedure
(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: Always refer to the A/C Underhood Specifi-
cation Label for the refrigerant fill capacity of the
vehicle being serviced.

(1) Use a manifold gauge and check the liquid line

pressure.

(2) Attach a clamp-on thermocouple to the liquid

line near the A/C condenser.

(3) The vehicle must be in the following modes:
• Automatic transaxle in park or manual trans-

axle in neutral.

• Engine at idle

• A/C controls set to outside air

• Panel mode

• A/C on full cool

• Blower motor on highest speed

• Vehicle windows closed
(4) Operate the A/C system for a couple of minutes

to allow the system to stabilize.

(5) Observe liquid line pressure and temperature.

Using the Charge Determination Chart (Fig. 3) deter-
mine where the A/C system is currently operating. If
the A/C system is not in the proper range, reclaim all
the refrigerant and recharge the refrigerant system.

REFRIGERANT SYSTEM RECOVERY

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

A R-134a refrigerant recovery/recycling/charging

station that meets SAE Standard J2210 must be
used to recover the refrigerant from an R-134a refrig-
erant system. Refer to the operating instructions sup-
plied by the equipment manufacturer for the proper
care and use of this equipment.

REFRIGERANT SYSTEM EVACUATE

NOTE: Special effort must be used to prevent mois-
ture from entering the A/C system oil. Moisture in
the oil is very difficult to remove and will cause a
reliability problem with the compressor.

If an A/C compressor designed to use R-134a refrig-

erant is left open to the atmosphere for an extended
period of time. It is recommended that the refriger-
ant oil be drained and replaced with new oil or a new
A/C compressor be used. This will eliminate the pos-
sibility of contaminating the refrigerant system.

If the refrigerant system has been open to the

atmosphere, it must be evacuated before the system
can be filled. Moisture and air mixed with the refrig-
erant will raise the compressor head pressure above
acceptable operating levels. This will reduce the per-
formance of the air conditioner and damage the A/C
compressor. Moisture will boil at near room tempera-
ture when exposed to vacuum. A R-134a refrigerant
recovery/recycling/charging station that meets SAE
Standard J2210 must be used to evacuate the refrig-
erant system. See the operating instructions supplied
by the equipment manufacturer for proper care and
use of this equipment. To evacuate the refrigerant
system, use the following procedure:

NOTE: When connecting the service equipment
couplings to the refrigerant system service ports,
be certain that the valve of each coupling is fully
closed. This will reduce the amount of effort
required to make the connection.

(1) Recover the refrigerant system (Refer to 24 -

HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFRIGERANT SYS-
TEM RECOVERY).

(2) Connect a suitable charging station, refrigerant

recovery machine or a manifold gauge set with vac-
uum pump and refrigerant recovery equipment.

(3) Open the suction and discharge valves and

start the vacuum pump. The vacuum pump should
run a minimum of 45 minutes prior to charge to
eliminate all moisture in system. When the suction
gauge reads -88 kPa (-26 in. Hg) vacuum or greater
for 30 minutes, close all valves and turn off vacuum
pump. If the system fails to reach specified vacuum,
the refrigerant system likely has a leak that must be
corrected. If the refrigerant system maintains speci-
fied vacuum for at least 30 minutes, start the vac-
uum pump, open the suction and discharge valves.
Then allow the system to evacuate an additional 10
minutes.

(4) Close all valves. Turn off and disconnect the

vacuum pump.

24 - 40

PLUMBING

PL/SRT-4

PLUMBING (Continued)

(5) Charge the refrigerant system (Refer to 24 -

HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFRIGERANT SYS-
TEM CHARGE).

REFRIGERANT SYSTEM CHARGE

NOTE: Always refer to the A/C Underhood Specifi-
cation Label for the refrigerant fill capacity of the
vehicle being serviced.

After all refrigerant system leaks have been

repaired and the refrigerant system has been evacu-
ated, a refrigerant charge can be injected into the
system. For the proper amount of the refrigerant
charge, always refer to the A/C Underhood Specifica-
tion Label located in the engine compartment. An
R-134a refrigerant recovery/recycling/charging sta-

tion that meets SAE Standard J2210 must be used to
charge the refrigerant system with R-134a refriger-
ant. See the operating instructions supplied by the
equipment manufacturer for proper care and use of
this equipment.

CHARGING PROCEDURE

CAUTION: A small amount of refrigerant oil is
removed from the A/C system each time the refrig-
erant system is recovered and evacuated. Before
charging the A/C system, you MUST replenish any
oil lost during the recovery process. Refer the
equipment manufacturer instructions for more infor-
mation.

(1) Evacuate the refrigerant system. (Refer to 24 -

HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFRIGERANT SYS-
TEM EVACUATE).

(2) A manifold gauge set and a R-134a refrigerant

recovery/recycling/charging station that meets SAE
Standard J2210 should still be connected to the
refrigerant system.

(3) Measure the proper amount of refrigerant and

heat it to 52° C (125° F) with the charging station.

Fig. 3 Charge Determination Chart (Ambient Test Condition 85° F)

PL/SRT-4

PLUMBING

24 - 41

PLUMBING (Continued)

See the operating instructions supplied by the equip-
ment manufacturer for proper use of this equipment.

(4) Open both the suction and discharge valves,

then open the charge valve to allow the heated
refrigerant to flow into the system.

(5) When the transfer of refrigerant has stopped,

close both the suction and discharge valves.

(6) If all of the refrigerant charge did not transfer

from the dispensing device, open all of the windows
in the vehicle and set the heater-air conditioner con-
trols so that the compressor is engaged and the
blower motor is operating at its lowest speed setting.
Run the engine at a steady high idle (about 1400
rpm). If the compressor will not engage, test the com-
pressor clutch control circuit and repair as required.

(7) Open the suction valve to allow the remaining

refrigerant to transfer to the refrigerant system.

WARNING: Take care not to open the discharge
(high pressure) valve at this time. Failure to follow
this warning can result in possible personal injury
or death.

(8) Close the suction valve and test the system

performance. (Refer to 24 - HEATING & AIR CON-
DITIONING - DIAGNOSIS AND TESTING - A/C
PERFORMANCE).

(9) Disconnect the charging station and manifold

gauge set from the refrigerant system service ports.

(10) Reinstall the caps onto the refrigerant system

service ports.

A/C COMPRESSOR

DESCRIPTION

A/C COMPRESSOR

The A/C compressor (Fig. 4) used on this vehicle

has an aluminum swash plate, teflon coated pistons
and aluminum sleeveless cylinder walls. A A/C high
pressure switch is located on the back cover of the
compressor.

The compressor is secured to the lower front strut-

to-engine bracket with four bolts. The lower front
strut-to-engine bracket is located on the lower, for-
ward skirt of the engine block which is located in the
right front corner of the engine compartment.

The compressor cannot be repaired. If faulty or

damaged,

the

entire

compressor

unit

must

replaced. The compressor clutch, pulley, clutch coil
and the A/C high pressure switch are available for
service replacement.

The compressor front shaft seal is not serviceable.

If a leak is detected at the shaft seal, the compressor
must be replaced as a unit.

HIGH PRESSURE RELIEF VALVE

The high pressure relief valve vents the system

when a discharge pressure of 3445 to 4135 kPa (500
to 600 psi) or above is reached. The valve closes
when a minimum discharge pressure of 2756 kPa
(400 psi) is reached.

The high pressure relief valve vents only enough

refrigerant to reduce the system pressure, and then
re-seats itself. The majority of the refrigerant is con-
served in the system. If the valve vents refrigerant, it
does not mean that the valve is faulty.

The high pressure relief valve is only serviced as a

part of the A/C compressor assembly and is factory-
calibrated and cannot be adjusted or repaired and,
must not be removed or otherwise disturbed.

OPERATION

A/C COMPRESSOR

The A/C compressor is driven by the engine

through an electric clutch, drive pulley and belt
arrangement. The compressor is lubricated by refrig-
erant 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 the high-pressure refrigerant vapor to the
condenser through the compressor discharge port.

The compressor cannot be repaired. If faulty or

damaged, the entire compressor assembly must be

Fig. 4 A/C Compressor

1 - A/C COMPRESSOR
2 - MOUNTING BOLTS
3 - LOWER FRONT STRUT-TO-ENGINE BRACKET

24 - 42

PLUMBING

PL/SRT-4

PLUMBING (Continued)

replaced. The compressor clutch, pulley and clutch
coil are available for service.

HIGH PRESSURE RELIEF VALVE

The high pressure relief valve vents the A/C sys-

tem when a discharge pressure of 3445 to 4135 kPa
(500 to 600 psi) or above is reached. The high pres-
sure relief valve closes when a minimum discharge
pressure of 2756 kPa (400 psi) is reached.

The high pressure relief valve vents only enough

refrigerant to reduce the A/C system pressure, and
then re-seats itself. The majority of the refrigerant is
conserved in the A/C system. If the valve vents
refrigerant, it does not mean that the valve is faulty.

The high pressure relief valve is factory-calibrated.

The high pressure relief valve cannot be adjusted or
repaired, and must not be removed or otherwise dis-
turbed. The high pressure relief valve is only ser-
viced as a part of the A/C compressor.

DIAGNOSIS AND TESTING

A/C COMPRESSOR NOISE

When investigating an A/C system related noise,

you must first know the conditions under which the
noise occurs. These conditions include: weather, vehi-
cle speed, transmission in gear or neutral, engine
speed, engine temperature, and any other special
conditions. Noises that develop during A/C operation
can often be misleading. For example: What sounds
like a failed front main bearing or connecting rod,
may be caused by loose bolts, nuts, mounting brack-
ets, or a loose A/C clutch assembly.

NOTE: Prior to a vehicle being removed from ser-
vice or stored for more than two weeks, the A/C
compressor should be operated to ensure adequate
refrigerant oil distribution throughout the system
components. Turn on the A/C for a minimum of five
minutes with outside air and the highest blower
speed selected.

Drive belts are speed sensitive. At different engine

speeds and depending upon belt tension, belts can
develop noises that are mistaken for an A/C compres-
sor noise. Improper belt tension can cause a mislead-
ing noise when the A/C clutch is engaged, which may
not occur when the A/C clutch is disengaged. Check
the accessory drive belt condition and tension as
described in Cooling before beginning this procedure.

(1) Select a quiet area for testing. Duplicate the

complaint conditions as much as possible. Switch the
A/C compressor on and off several times to clearly
identify the compressor noise. Listen to the A/C com-
pressor while the clutch is engaged and disengaged.
Probe the A/C compressor with an engine stethoscope

or a long screwdriver with the handle held to your
ear to better localize the source of the noise.

(2) Loosen all of the compressor mounting hard-

ware and retighten. Tighten the A/C clutch mounting
bolt. Be certain that the clutch field coil is mounted
securely to the A/C compressor, and that the clutch
plate and pulley are properly aligned and have the
correct air gap (Refer to 24 - HEATING & AIR CON-
DITIONING/CONTROLS/A/C

COMPRESSOR

CLUTCH - INSTALLATION).

(3) To duplicate a high-ambient temperature condi-

tion (high head pressure), restrict the air flow
through the A/C condenser. Install a manifold gauge
set to be certain that the discharge pressure does not
exceed 2760 kPa (400 psi).

(4) Check the refrigerant system plumbing for

incorrect routing, rubbing or interference, which can
cause unusual noises. Also check the refrigerant lines
for kinks or sharp bends that will restrict refrigerant
flow, which can cause noises.

(5) If the noise is from opening and closing of the

high pressure relief valve, recover, evacuate, and
recharge the refrigerant system (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING - STAN-
DARD PROCEDURE - REFRIGERANT SYSTEM
RECOVERY) and (Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING - STANDARD PRO-
CEDURE - REFRIGERANT SYSTEM EVACUATE)
and (Refer to 24 - HEATING & AIR CONDITION-
ING/PLUMBING

STANDARD

PROCEDURE

REFRIGERANT SYSTEM CHARGE). If the high
pressure relief valve still does not seat properly,
replace the A/C compressor (Refer to 24 - HEATING
&

AIR

CONDITIONING/PLUMBING/A/C

COM-

PRESSOR - REMOVAL).

(6) If the noise is from liquid slugging on the A/C

suction line, check the refrigerant oil level and the
refrigerant system charge.

(7) If the noise continues, replace the A/C compres-

sor and repeat Step 1.

REMOVAL

WARNING: Review the warnings and cautions in the
front of this section before performing the following
operation (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING - WARNING - A/C SYSTEM) and
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - CAUTION - A/C SYSTEM).

(1) Disconnect and isolate the negative battery

cable.

(2) Recover the refrigerant from the refrigerant

system (Refer to 24 - HEATING & AIR CONDITION-
ING - STANDARD PROCEDURE - REFRIGERANT
SYSTEM RECOVERY).

PL/SRT-4

PLUMBING

24 - 43

A/C COMPRESSOR (Continued)

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