1998 DODGE RAM 1500 refrigerant type

(10) Drain engine oil. Remove and discard the oil
filter (Refer to 9 - ENGINE/LUBRICATION/OIL FIL-
TER - REMOVAL).
(11) Install the drain plug. Tighten the plug to 50
N´m (37 ft. lbs.) torque.
(12) Install a new oil filter (Refer to 9 - ENGINE/
LUBRICATION/OIL FILTER - INSTALLATION).
(13) Fill engine crankcase with the specified
amount and grade of oil (Refer to LUBRICATION &
MAINTENANCE/FLUID TYPES - SPECIFICA-
TIONS).
(14) Connect the negative cable(s) to the battery.
(15) Start the engine and check for any leaks.
REMOVAL
REMOVAL - ENGINE
(1) Disconnect both battery negative cables.
(2) Disconnect engine grid heater harness at grid
heater relays.
(3) Disconnect electrical connections from rear of
alternator.
(4) Recover A/C refrigerant. (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING - STAN-
DARD PROCEDURE).
(5) Raise vehicle on a hoist.
(6) Drain engine coolant (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(7) Remove engine oil drain plug and drain engine
oil.
(8) Reinstall drain plug. Tighten to 50N´m (37 ft.
lbs.) torque.
(9) Lower the vehicle.
(10) Remove fan/drive assembly. Refer to Section 7
± Fan/Drive Removal
(11) Remove radiator upper hose.
(12) Remove upper fan shroud mounting bolts.
(13) Disconnect the coolant recovery bottle hose
from the radiator fill neck and remove bottle.
(14) Using a 36mm wrench, remove viscous fan/
drive assembly. (Refer to 7 - COOLING/ENGINE/RA-
DIATOR FAN - REMOVAL).
(15) Remove cooling fan and shroud together.
(16) Disconnect heater core supply and return
hoses from the cylinder head fitting and coolant pipe.
(17) Raise vehicle on a hoist.
(18) Remove transmission and transfer case (if
equipped).
(19) Disconnect exhaust pipe from turbocharger
extension pipe.
(20) Disconnect engine harness to vehicle harness
connectors.
(21) Remove starter motor (Refer to 8 - ELECTRI-
CAL/STARTING/STARTER MOTOR - REMOVAL).(22) Remove flywheel/flexplate.
(23) Remove transmission adapter
(24) Disconnect A/C suction/discharge hose from
the rear of the A/C compressor.
(25) Lower vehicle.
(26) Disconnect lower radiator hose from radiator
outlet.
(27) Automatic transmission models:
(28) Disconnect transmission oil cooler lines from
in front of radiator using special tool #6931
(29) Remove radiator. (Refer to 7 - COOLING/EN-
GINE/RADIATOR - REMOVAL).
(30) If A/C equipped, disconnect A/C condenser
refrigerant lines.
(31) Disconnect charge air cooler piping.
(32) Remove charge air cooler mounting bolts.
(33) Remove charge air cooler (and A/C condenser
if equipped) from vehicle.
(34) Remove damper and speed indicator ring from
front of engine.
(35) Disconnect engine block heater connector.
(36) Disconnect A/C compressor and pressure sen-
sor electrical connectors.
(37) Remove the passenger battery ground cable
from the engine block. Remove the driver side bat-
tery ground cable from the engine block.
(38) Remove power steering pump from engine by
removing 3 bolts.
(39) Remove accelerator linkage cover.
(40) Disconnect cables from on-engine APPS.
(41) Disconnect the ECM power connector.
(42) Disconnect the ECM ground wire from the
hydroform screw.
(43) Disconnect the fuel supply and return hoses.
(44) Remove the cylinder head cover. (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - REMOVAL).
(45) Disconnect the 3 injector harness connectors
at the rocker housing. Disconnect the wire harnesses
from the injectors.
(46) Remove the rear engine lift bracket.
(47) Remove cylinder #4, #5, and #6 intake and
exhaust rocker arms, pedestals, and push tubes. Note
the original location for re-assembly.
(48) Loosen #6 fuel line shield bolts and rotate
shield out of the way.
(49) Remove cylinder #5 and #6 high pressure fuel
lines. Remove the fuel connector tube nut and fuel
connector tube. Remove cylinder #5 and #6 fuel injec-
tor.
(50) Remove rocker housing.
DRENGINE 5.9L DIESEL 9 - 241
ENGINE 5.9L DIESEL (Continued)

and coil are the only serviced parts on the compres-
sor.
A/C compressor clutch engagement is controlled by
several components: the A/C-heater control, A/C pres-
sure transducer, A/C compressor clutch relay, evapo-
rator temperature sensor and the powertrain control
module (PCM). The PCM may delay compressor
clutch engagement for up to thirty seconds (Refer to
8 - ELECTRICAL/ELECTRONIC CONTROL MOD-
ULES/POWERTRAIN CONTROL MODULE -
DESCRIPTION).
DIAGNOSIS AND TESTING - A/C COMPRESSOR
CLUTCH COIL
For circuit descriptions and diagrams, (Refer to
Appropriate Wiring Information). The battery must
be fully-charged before performing the following
tests. Refer to Battery for more information.
(1) Connect an ammeter (0 to 10 ampere scale) in
series with the clutch coil terminal. Use a voltmeter
(0 to 20 volt scale) with clip-type leads for measuring
the voltage across the battery and the compressor
clutch coil.
(2) With the A/C-heater controls in any A/C mode,
and the blower motor switch in the lowest speed
position, start the engine and run it at normal idle.
(3) The compressor clutch coil voltage should read
within 0.2 volts of the battery voltage. If there is
voltage at the clutch coil, but the reading is not
within 0.2 volts of the battery voltage, test the clutch
coil feed circuit for excessive voltage drop and repair
as required. If there is no voltage reading at the
clutch coil, use a DRB IIItscan tool and (Refer to
Appropriate Diagnostic Information) for testing of thecompressor clutch circuit and PCM control. The fol-
lowing components must be checked and repaired as
required before you can complete testing of the clutch
coil:
²Fuses in the junction block and the power distri-
bution center (PDC)
²A/C-heater control
²A/C compressor clutch relay
²A/C pressure transducer
²Evaporator temperature sensor
²Powertrain control module (PCM)
(4) The compressor clutch coil is acceptable if the
current draw measured at the clutch coil is within
specifications with the electrical system voltage at
11.5 to 12.5 volts (Refer to 24 - HEATING & AIR
CONDITIONING - SPECIFICATIONS). This should
only be checked with the work area temperature at
21É C (70É F). If system voltage is more than 12.5
volts, add electrical loads by turning on electrical
accessories until the system voltage drops below 12.5
volts.
(a) If the clutch coil current reading is above
specifications, the coil is shorted and should be
replaced.
(b) If the clutch coil current reading is zero, the
coil is open and should be replaced.
STANDARD PROCEDURE - A/C COMPRESSOR
CLUTCH BREAK-IN
After a new compressor clutch has been installed,
cycle the compressor clutch approximately twenty
times (five seconds on, then five seconds off). During
this procedure, set the A/C-heater control to the
Recirculation Mode, the blower motor switch in the
highest speed position, and the engine speed at 1500
to 2000 rpm. This procedure (burnishing) will seat
the opposing friction surfaces and provide a higher
compressor clutch torque capability.
REMOVAL
The refrigerant system can remain fully-charged
during compressor clutch, rotor, or coil replacement.
The compressor clutch can be serviced in the vehicle.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the serpentine drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(3) Disconnect the compressor clutch coil wire har-
ness connector.
(4) Remove the bolts that secure the compressor to
the mounting bracket.
(5) Remove the compressor from the mounting
bracket. Support the compressor in the engine com-
partment while servicing the clutch.
Fig. 1 Compressor Clutch - Typical
1 - CLUTCH PLATE
2 - SHAFT KEY (not used on KJ)
3 - ROTOR
4 - COIL
5 - CLUTCH SHIMS
6 - SNAP RING
7 - SNAP RING
24 - 10 CONTROLSDR
A/C COMPRESSOR CLUTCH/COIL (Continued)

The illumination lamps are available for service
replacement.
REMOVAL
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 AN ACCIDENTAL
AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the center bezel from the instrument
panel (Refer to 23 - BODY/INSTRUMENT PANEL/
INSTRUMENT PANEL CENTER BEZEL -
REMOVAL).
(3) Remove the screws that secure the A/C-heater
control to the instrument panel (Fig. 14).
INSTALLATION
(1) Position the A/C-heater control onto the instru-
ment panel center bezel and install the retaining
screws. Tighten the screws to 2.2 N´m (20 in. lbs.).
(2) Install the instrument panel center bezel (Refer
to 23 - BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL CENTER BEZEL - INSTALLATION).
(3) Reconnect the battery negative cable.
A/C PRESSURE TRANSDUCER
DESCRIPTION
The A/C pressure transducer is a switch that is
installed on a fitting located on the refrigerant dis-
charge line between the compressor and the con-
denser in the front corner of the engine
compartment. An internally threaded hex fitting on
the transducer connects it to the externally threaded
Schrader-type fitting on the discharge line. A rubber
O-ring seals the connection between the transducer
and the discharge line fitting. Three terminals within
a molded plastic connector receptacle on the top of
the transducer connect it to the vehicle electrical sys-
tem through a wire lead and connector of the head-
lamp and dash wire harness.
Fig. 12 Single Zone HVAC Control
1 - MOUNTING TAB (4)
2 - A/C BUTTON
3 - SIDEVIEW MIRROR DEFROSTER BUTTON (IF EQUIPED)
4 - MODE CONTROL SWITCH
5 - TEMPERATURE CONTROL SWITCH
6 - BLOWER MOTOR SWITCH
Fig. 13 Dual Zone A/C Control
1 - A/C BUTTON
2 - MAX. A/C BUTTON
3 - SIDEVIEW MIRROR DEFROSTER BUTTON (IF EQUIPED)
4 - MOUNTING TABS (4)
5 - DRIVERSIDE TEMPERATURE CONTROL
6 - PASSENGERSIDE TEMPERATURE CONTROL
7 - MODE CONTROL SWITCH
8 - BLOWER MOTOR SWITCH
Fig. 14 A/C-Heater Control - Typical, Rear View
1 - MOUNTING TAB (4)
2 - SCREW (4)
3 - A/C-HEATER CONTROL ELECTRICAL CONNECTOR
4 - HEATED SIDEVIEW MIRROR ELECTRICAL CONNECTOR
5 - A/C-HEATER CONTROL
DRCONTROLS 24 - 15
A/C HEATER CONTROL (Continued)

The A/C pressure transducer cannot be adjusted or
repaired and, if faulty or damaged, it must be
replaced.
OPERATION
The A/C pressure transducer monitors the pres-
sures in the high side of the refrigerant system
through its connection to a fitting on the discharge
line. The transducer will change its internal resis-
tance in response to the pressures it monitors. The
Powertrain Control Module (PCM) or the Engine
Control Module (ECM) depending on engine applica-
tion, provides a five volt reference signal and a sen-
sor ground to the transducer, then monitors the
output voltage of the transducer on a sensor return
circuit to determine refrigerant pressure. The PCM/
ECM is programmed to respond to this and other
sensor inputs by controlling the operation of the air
conditioning compressor clutch and the radiator cool-
ing fan to help optimize air conditioning system per-
formance and to protect the system components from
damage. The A/C pressure transducer input to the
PCM/ECM will also prevent the air conditioning com-
pressor clutch from engaging when ambient temper-
atures are below about 10É C (50É F) due to the
pressure/temperature relationship of the refrigerant.
The Schrader-type valve in the discharge line fitting
permits the A/C pressure transducer to be removed
or installed without disturbing the refrigerant in the
system. The A/C pressure transducer is diagnosed
using a DRBIIItscan tool. Refer to the appropriate
diagnostic information.
DIAGNOSIS AND TESTING - A/C PRESSURE
TRANSDUCER
The A/C pressure transducer is tested using a
DRBIIItscan tool. Refer to the appropriate diagnos-
tic information. Before testing the A/C pressure
transducer, be certain that the transducer wire har-
ness connection is clean of corrosion and properly
connected. For the air conditioning system to operate,
an A/C pressure transducer voltage reading between
0.451 and 4.519 volts is required. Voltages outside
this range indicate a low or high refrigerant system
pressure condition to the Powertrain Control Module
(PCM) or Engine Control Module (ECM) depending
on engine application. The PCM/ECM is programmed
to respond to a low or high refrigerant system pres-
sure by suppressing operation of the compressor.
Refer to the A/C Pressure Transducer Voltage chart
for the possible conditions indicated by the trans-
ducer voltage reading.
A/C PRESSURE TRANSDUCER VOLTAGE
CHART
Voltage Possible Indication
0.0 1. No sensor supply voltage from
PCM/ECM.
2. Shorted sensor circuit.
3. Faulty transducer.
0.150 TO 0.450 1. Ambient temperature below
10É C (50É F).
2. Low refrigerant system
pressure.
0.451 TO 4.519 1. Normal refrigerant system
pressure.
4.520 TO 4.850 1. High refrigerant system
pressure.
5.0 1. Open sensor circuit.
2. Faulty transducer.
REMOVAL
NOTE: Note: It is not necessary to discharge the
refrigerant system to replace the A/C pressure
transducer.
(1) Disconnect and isolate the battery negative
cable.
(2) Disconnect the wire harness connector from the
A/C pressure transducer.
(3) Remove the A/C pressure transducer from the
fitting on the discharge line (Fig. 15).
(4) Remove the O-ring seal from the A/C pressure
transducer fitting and discard.
INSTALLATION
NOTE: Replace the O-ring seal before installing the
A/C pressure transducer.
(1) Lubricate a new rubber O-ring seal with clean
refrigerant oil and install it on the A/C pressure
transducer fitting. Use only the specified O-rings as
they are made of a special material for the R-134a
system. Use only refrigerant oil of the type recom-
mended for the A/C compressor in the vehicle.
(2) Install and tighten the A/C pressure transducer
onto the discharge line fitting. The transducer should
be hand-tightened securely onto the discharge line
fitting.
(3) Connect the wire harness connector to the A/C
pressure transducer.
24 - 16 CONTROLSDR
A/C PRESSURE TRANSDUCER (Continued)

DIAGNOSIS AND TESTING - REFRIGERANT
SYSTEM LEAKS
WARNING: R-134a SERVICE EQUIPMENT OR VEHI-
CLE A/C SYSTEM SHOULD NOT BE PRESSURE
TESTED OR LEAK TESTED WITH COMPRESSED
AIR. MIXTURE OF AIR and R-134a CAN BE COM-
BUSTIBLE AT ELEVATED PRESSURES. THESE MIX-
TURES ARE POTENTIALLY DANGEROUS AND MAY
RESULT IN FIRE OR EXPLOSION CAUSING INJURY
OR PROPERTY DAMAGE.
AVOID BREATHING A/C REFRIGERANT AND LUBRI-
CANT VAPOR OR MIST. EXPOSURE MAY IRRITATE
EYES, NOSE AND THROAT. USE ONLY APPROVED
SERVICE EQUIPMENT MEETING SAE REQUIRE-
MENTS TO DISCHARGE R-134a SYSTEM. IF ACCI-
DENTAL SYSTEM DISCHARGE OCCURS,
VENTILATE WORK AREA BEFORE RESUMING SER-
VICE.
NOTE: The refrigerant system does come from the
factory with a yellow tracer dye already installed to
aid in detection of leaks.
If the A/C system is not cooling properly, determine
if the refrigerant system is fully charged with
R-134a. This is accomplished by performing a system
Charge Level-Check or Fill. If while performing this
test A/C liquid line pressure is less than 345 kPa (50
psi) proceed to System Empty procedure. If liquid
line pressure is greater than 345 kPa (50 psi) proceed
to System Low procedure. If the refrigerant system is
empty or low in refrigerant charge, a leak at any line
fitting or component seal is likely. A review of the fit-
tings, lines and components for oily residue is an
indication of the leak location. To detect a leak in the
refrigerant system, perform one of the following pro-
cedures as indicated by the symptoms.
SYSTEM EMPTY
(1) Evacuate the refrigerant system to the lowest
degree of vacuum possible (approx. 28 in Hg.). Deter-
mine if the system holds a vacuum for 15 minutes. If
vacuum is held, a leak is probably not present. If sys-
tem will not maintain vacuum level, proceed with
this procedure.(2) Prepare a 0.284 Kg. (10 oz.) refrigerant charge
to be injected into the system.
(3) Connect and dispense 0.284 Kg. (10 oz.) of
refrigerant into the evacuated refrigerant system.
(4) Proceed to Step 2 of System Low procedure.
SYSTEM LOW
(1) Determine if there is any (R-134a) refrigerant
in the system.
(2) Position the vehicle in a wind free work area.
This will aid in detecting small leaks.
(3) Bring the refrigerant system up to operating
temperature and pressure. This is done by allowing
the engine to run for five minutes with the system
set to the following:
²Transmission in Park or Neutral with parking
brake set
²Engine idling at 700 rpm
²A/C controls set in 100 percent outside air
²Blower switch in the high A/C position
²A/C in the ON position
²Open all windows
CAUTION: A leak detector designed for R-12 refrig-
erant (only) will not detect leaks in a R-134a refrig-
erant system.
(4) Shut off the vehicle and wait 2 to 7 minutes.
Then use an Electronic Leak Detector that is
designed to detect R-134a type refrigerant and search
for leaks. Fittings, lines, or components that appear
to be oily usually indicates a refrigerant leak. To
inspect the evaporator core for leaks, insert the leak
detector probe into the drain tube opening or a heat
duct. A R-134a dye is available to aid in leak detec-
tion, use only DaimlerChrysler approved refrigerant
dye.
24 - 44 PLUMBINGDR
PLUMBING (Continued)

STANDARD PROCEDURE
STANDARD PROCEDURE - HANDLING TUBING
AND FITTINGS
CAUTION: The system must be completely empty
before opening any fitting or connection in the
refrigeration system. Open fittings with caution
even after the system has been emptied. If any
pressure is noticed as a fitting is loosened,
retighten fitting and evacuate the system again.
A good rule for the flexible hose lines is to keep the
radius of all bends at least 10 times the diameter of
the hose. Sharper bends will reduce the flow of
refrigerant. The flexible hose lines should be routed
so they are at least 3 inches (80 mm) from the
exhaust manifold. Inspect all flexible hose lines to
make sure they are in good condition and properly
routed.
The use of correct wrenches when making connec-
tions is very important. Improper wrenches or
improper use of wrenches can damage the fittings.
The internal parts of the A/C system will remain sta-
ble as long as moisture-free refrigerant and refrig-
erant oil is used. Abnormal amounts of dirt,
moisture or air can upset the chemical stability.
This may cause operational troubles or even seri-
ous damage if present in more than very small
quantities. Before disconnecting a component,
clean the outside of the fittings thoroughly to pre-
vent contamination from entering the refrigerant
system.
When opening a refrigeration system, have every-
thing you will need to repair the system ready. This
will minimize the amount of time the system must
be opened. Cap or plug all lines and fittings as
soon as they are opened. This will help prevent the
entrance of dirt and moisture. All new lines and
components should be capped or sealed until they
are ready to be used. Before connecting a compo-
nent, clean the outside of the fittings thoroughly to
prevent contamination from entering the refrigerant
system.
All tools, including the refrigerant dispensing mani-
fold, the manifold gauge set, and test hoses should
be kept clean and dry.
Kinks in the refrigerant tubing or sharp bends in
the refrigerant hose lines will greatly reduce the
capacity of the entire system. High pressures are pro-
duced in the system when it is operating. Extreme
care must be exercised to make sure that all connec-
tions are pressure tight. Dirt and moisture can enter
the system when it is opened for repair or replace-
ment of lines or components. The refrigerant oil willabsorb moisture readily out of the air. This moisture
will convert into acids within a closed system.
STANDARD PROCEDURE - DIODE
REPLACEMENT
(1) Disconnect and isolate the battery negative
cable. If the vehicle has dual batteries, remove the
negative cable from both batteries.
(2) Locate the diode in the harness, and remove
the protective covering.
(3) Remove the diode from the harness. Note the
direction of current flow (Fig. 1).
(4) Remove the insulation from the wires in the
harness. Only remove enough insulation to solder in
the new diode.
(5) Install the new diode in the harness, making
sure current flow is correct. If necessary refer to the
appropriate wiring diagram for current flow.
(6) Solder the connections together using rosin
core type solder only.Do not use acid core solder.
(7) Tape the diode to the harness using electrical
tape. Make sure the diode is completely sealed from
the elements.
(8) Reconnect the battery negative cable(s) and
test the affected systems.
Fig. 1 Diode Identification
1 - CURRENT FLOW
2 - BAND INDICATES CURRENT FLOW
3 - DIODE AS SHOWN IN WIRING DIAGRAMS
DRPLUMBING 24 - 45
PLUMBING (Continued)

After the system has been tested for leaks and
evacuated, a refrigerant (R-134a) charge can be
injected into the system.
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) If using a separate vacuum pump close all
valves before disconnecting pump. Connect manifold
gauge set to the A/C service ports.
NOTE: Always refer to the underhood HVAC Speci-
fication label for the refrigerant fill level of the vehi-
cle being serviced.
(2) Measure refrigerant (refer to capacities). Refer
to the instructions provided with the equipment
being used.
(3) Verify engine is shut off. Open the suction and
discharge valves. Open the charge valve to allow the
refrigerant to flow into the system. When the trans-
fer of refrigerant has stopped, close the suction and
discharge valve.
(4) If all of the charge did not transfer from the
dispensing device, put vehicle controls into the fol-
lowing mode:
²Automatic transmission in park or manual
transmission in neutral
²Engine at idle
²A/C mode control set to outside air
²A/C mode control set to panel mode
²A/C temperature control set to full cool
²Blower motor control set on highest speed
²Vehicle windows closed
If the A/C compressor does not engage, test the
compressor clutch control circuit and correct any fail-
ure (Refer to 8 - ELECTRICAL/WIRING DIAGRAM
INFORMATION - DIAGNOSIS AND TESTING).
(5) Open the suction valve to allow the remaining
refrigerant to transfer to the system.
WARNING: TAKE CARE NOT TO OPEN THE DIS-
CHARGE (HIGH-PRESSURE) VALVE AT THIS TIME.
(6) Close all valves and test the A/C system perfor-
mance.
(7) Disconnect the charging station or manifold
gauge set. Install the service port caps.
REFRIGERANT CHARGE CAPACITY
The R-134a refrigerant system charge capacity for
this vehicle can be found on the underhood HVAC
specfication tag.
A/C COMPRESSOR
DESCRIPTION
DESCRIPTION - A/C COMPRESSOR
The A/C system on models equipped with the 5.9L
engine use a Sanden SD-7 reciprocating swash plate-
type compressor. This compressor has a fixed dis-
placement of 165 cubic centimeter (10.068 cubic
inches) and has both the suction and discharge ports
located on the cylinder head.
The A/C system on models equipped with the 3.7L,
4.7L and 5.7L engines use a Denso 10S17 reciprocat-
ing swash plate-type compressor. This compressor
has a fixed displacement of 170 cubic centimeter and
has both the suction and discharge ports located on
the cylinder head.
A label identifying the use of R-134a refrigerant is
located on both A/C compressors.
DESCRIPTION - HIGH PRESSURE RELIEF
VALVE
A high pressure relief valve is located on the com-
pressor cylinder head, which is on the rear of the
compressor. This mechanical valve is designed to
vent refrigerant from the system to protect against
damage to the compressor and other system compo-
nents, caused by condenser air flow restriction or an
overcharge of refrigerant.
OPERATION
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, which is then
pumped to the condenser through the compressor dis-
charge port.
The compressor cannot be repaired. If faulty or
damaged, the entire compressor assembly must be
replaced. The compressor clutch, pulley and clutch
coil are available for service.
OPERATION - 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
24 - 48 PLUMBINGDR
PLUMBING (Continued)

INSTALLATION
NOTE: If a replacement compressor is being
installed, be certain to check the refrigerant oil
level. See Refrigerant Oil Level in this group for the
procedures. Use only refrigerant oil of the type rec-
ommended for the compressor in the vehicle.
(1) Install the compressor onto the mounting
bracket.
(2) On the 3.7L and 4.7L engines, install and
tighten the bolts in the following sequence (Fig. 7):
²Install the inner front bolt #3 and hand tight-
ened.
²Install the outer front bolt #2 and hand tight-
ened.
²Install the rear bolt #1 and hand tightened.
²Tightened the inner front bolt #3 to 40 N´m (30
ft. lbs.).
²Tightened the outer front bolt #2 to 55 N´m (41
ft. lbs.).
²Tightened the rear bolt #1 to 55 N´m (41 ft. lbs.).
(3) For the 5.7L Hemi engine, install and tighten
the bolts in the following sequence (Fig. 8):
²Install the two long bolts into the mounting
bracket and hand tightened.
²Install the rear bolt and hand tightened.²Tightened the two long bolts to 40 N´m (30 ft.
lbs.).
²Tightened the rear bolt to 55 N´m (41 ft. lbs.).
(4) For the 5.7L Hemi engine, install the generator
and A/C compressor support bracket and retaining
nuts and bolts. Tighten the nuts and bolts securely.
(5) For the 5.9L diesel engine, install and tighten
the bolts in the following sequence (Fig. 9):
²Install the four bolts into the mounting bracket
and hand tightened.
²Tightened the four bolts to 24 N´m (17 ft. lbs.).
(6) Remove the tape or plugs from the opened
refrigerant line fittings and compressor ports.
(7) Lubricate new rubber O-ring seals with clean
refrigerant oil and install them on the suction and
discharge line fittings. Use only the specified O-rings
as they are made of a special material for the R-134a
system. Use only refrigerant oil of the type recom-
mended for the A/C compressor in the vehicle.
(8) Install the suction and discharge line fittings
onto the compressor.
(9) Install the bolt or nuts (depending on engine
application) that secure the suction and discharge
line fittings to the compressor. Tighten the bolt or
nuts to 28 N´m (20 ft. lbs.).
(10) Connect the wire harness connector to the
compressor clutch coil.
Fig. 7 A/C Compressor - 3.7L Shown, 4.7L Typical
1 - BOLT #1
2 - BOLT #2
3 - BOLT #3
4 - A/C COMPRESSOR
5 - A/C CLUTCH AND PULLEY
6 - MOUNTING BRACKET
Fig. 8 A/C Compressor - 5.7L Hemi
1 - BOLT (2)
2 - A/C COMPRESSOR
3 - BOLT
4 - MOUNTING BRACKET
DRPLUMBING 24 - 51
A/C COMPRESSOR (Continued)