1998 DODGE RAM 1500 Serpentine belt

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 a factory-cali-
brated unit. The valve cannot be adjusted or
repaired, and must not be removed or otherwise dis-
turbed. The valve is only serviced as a part of the
compressor assembly.
DIAGNOSIS AND TESTING - A/C COMPRESSOR
When investigating an air conditioning related
noise, you must first know the conditions under
which the noise occurs. These conditions include:
weather, vehicle speed, transmission in gear or neu-
tral, engine speed, engine temperature, and any
other special conditions. Noises that develop during
air conditioning operation can often be misleading.
For example: What sounds like a failed front bearing
or connecting rod, may be caused by loose bolts, nuts,
mounting brackets, or a loose compressor clutch
assembly.
Drive belts are speed sensitive. At different engine
speeds and depending upon belt tension, belts can
develop noises that are mistaken for a compressor
noise. Improper belt tension can cause a misleading
noise when the compressor clutch is engaged, which
may not occur when the compressor clutch is disen-
gaged. Check the serpentine 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
compressor on and off several times to clearly iden-
tify the compressor noise. Listen to the compressor
while the clutch is engaged and disengaged. Probe
the compressor with an engine stethoscope or a long
screwdriver with the handle held to your ear to bet-
ter localize the source of the noise.
(2) Loosen all of the compressor mounting hard-
ware and retighten. Tighten the compressor clutch
mounting nut. Be certain that the clutch coil is
mounted securely to the compressor, and that the
clutch plate and rotor are properly aligned and have
the correct air gap (Refer to 24 - HEATING & AIR
CONDITIONING/CONTROLS/A/C COMPRESSOR
CLUTCH - INSTALLATION).
(3) To duplicate a high-ambient temperature condi-
tion (high head pressure), restrict the air flow
through the condenser. Install a manifold gauge set
or a DRBIIItscan tool to be certain that the dis-
charge 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 (Refer to 24 - HEATING
& AIR CONDITIONING/PLUMBING - STANDARD
PROCEDURE).
(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), (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - STANDARD
PROCEDURE - REFRIGERANT SYSTEM EVACU-
ATE) and (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING - STANDARD PROCEDURE -
REFRIGERANT SYSTEM CHARGE). If the high
pressure relief valve still does not seat properly,
replace the compressor (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING/A/C COMPRES-
SOR - REMOVAL).
(6) If the noise is from liquid slugging on the suc-
tion line, replace the accumulator (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING/AC-
CUMULATOR - REMOVAL) and check the refriger-
ant oil level and the refrigerant system charge (Refer
to 24 - HEATING & AIR CONDITIONING/PLUMB-
ING/REFRIGERANT OIL - STANDARD PROCE-
DURE) (Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING/ACCUMULATOR -
REMOVAL). If after replacing the accumulator the
slugging condition still exists then replace the com-
pressor.(Refer to 24 - HEATING & AIR CONDITION-
ING/PLUMBING/A/C COMPRESSOR - REMOVAL).
(7) If the liquid slugging condition continues fol-
lowing accumulator replacement, replace the com-
pressor and repeat Step 1.
REMOVAL
WARNING: REVIEW THE WARNINGS AND CAU-
TIONS IN THE FRONT OF THIS SECTION BEFORE
PERFORMING THE FOLLOWING OPERATION (Refer
to 24 - HEATING & AIR CONDITIONING/PLUMBING -
WARNING) and (Refer to 24 - HEATING & AIR CON-
DITIONING/PLUMBING - CAUTION).
NOTE: The A/C compressor may be removed and
repositioned without disconnecting the refrigerant
lines or discharging the refrigerant system. Dis-
charging is not necessary if servicing the compres-
sor clutch, clutch coil, engine, engine cylinder head
or the generator.
(1) Recover the refrigerant from the refrigerant
system (Refer to 24 - HEATING & AIR CONDITION-
DRPLUMBING 24 - 49
A/C COMPRESSOR (Continued)

ING/PLUMBING - STANDARD PROCEDURE -
REFRIGERANT RECOVERY).
(2) Disconnect and isolate the battery negative
cable.
(3) Remove the serpentine drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(4) Disconnect the A/C compressor clutch coil wire
harness connector.
(5) Depending on engine usage, remove the bolt or
nuts that secure the suction and discharge line fit-
tings to the A/C compressor.
(6) Disconnect the suction and discharge line fit-
tings from the A/C compressor.
(7) Remove the O-ring seals from the suction and
discharge line fittings and discard.
(8) Install plugs in, or tape over all of the opened
refrigerant line fittings and the compressor ports.
(9) If equipped with the 5.7L Hemi engine, remove
the nuts and bolts that secure the generator and A/C
compressor support bracket and remove the bracket
from the engine.
(10) Remove the bolts that secure the A/C com-
pressor to the mounting bracket (Fig. 4), (Fig. 5) or
(Fig. 6).
(11) Remove the A/C compressor from the engine
compartment.
Fig. 4 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. 5 A/C Compressor - 5.7L Hemi
1 - BOLT (2)
2 - A/C COMPRESSOR
3 - BOLT
4 - MOUNTING BRACKET
Fig. 6 A/C Compressor - 5.9L Diesel
1 - ENGINE BLOCK
2 - MOUNTING BRACKET
3 - A/C COMPRESSOR
4 - BOLT (4)
24 - 50 PLUMBINGDR
A/C COMPRESSOR (Continued)

(11) Install the serpentine drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
INSTALLATION).
(12) Reconnect the battery negative cable.
(13) Evacuate the refrigerant system (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE).
(14) Charge the refrigerant system (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE).
A/C CONDENSER
DESCRIPTION
The condenser is located in the air flow next to the
engine cooling radiator. The condenser is a heat
exchanger that allows the high-pressure refrigerant
gas being discharged by the compressor to give up its
heat to the air passing over the condenser fins.
OPERATION
When air passes through the condenser fins, the
high-pressure refrigerant gas within the A/C con-
denser gives up its heat. The refrigerant then con-
denses as it leaves the A/C condenser and becomes a
high-pressure liquid. The volume of air flowing over
the condenser fins is critical to the proper cooling
performance of the air conditioning system. There-fore, it is important that there are no objects placed
in front of the radiator grille openings at the front of
the vehicle or foreign material on the condenser fins
that might obstruct proper air flow. Also, any factory-
installed air seals or shrouds must be properly rein-
stalled following radiator or A/C condenser service.
The A/C condenser cannot be repaired and, if
faulty or damaged, it must be replaced.
REMOVAL
REMOVAL - 3.7, 4.7 AND 5.7L ENGINES
WARNING: REVIEW THE WARNINGS AND CAU-
TIONS IN THE FRONT OF THIS SECTION BEFORE
PERFORMING THE FOLLOWING OPERATION (Refer
to 24 - HEATING & AIR CONDITIONING/PLUMBING -
WARNING) and (Refer to 24 - HEATING & AIR CON-
DITIONING/PLUMBING - CAUTION).
(1) Disconnect and isolate the battery negative
cable.
(2) Recover the refrigerant from the refrigerant
system (Refer to 24 - HEATING & AIR CONDITION-
ING/PLUMBING - STANDARD PROCEDURE -
REFRIGERANT RECOVERY).
(3) Remove the nut that secures the discharge line
fitting to the condenser inlet port (Fig. 10).
(4) Disconnect the discharge line from the con-
denser.
(5) Remove the seal from the discharge line fitting
and discard.
(6) Install plugs in, or tape over the discharge line
fitting and condenser inlet port.
(7) Remove the plastic cover from the condenser
outlet stud.
(8) Remove the nut that secures the liquid line fit-
ting to the condenser outlet.
(9) Disconnect the liquid line from the condenser.
(10) Remove the seal from the liquid line fitting
and discard.
(11) Install plugs in, or tape over the liquid line
fitting and condenser outlet port.
(12) Disconnect the wire harness connector from
the condenser cooling fan motor (Fig. 11).
(13) Remove the two bolts that secure the con-
denser to the front upper crossmember.
(14) Remove the condenser/cooling fan assembly
from the vehicle.
(15) Place the condenser/cooling fan assembly on a
flat work area and remove the four screws that
secure the cooling fan to the condenser.
(16) Separate the cooling fan from the condenser.
Fig. 9 A/C Compressor - 5.9L Diesel
1 - ENGINE BLOCK
2 - MOUNTING BRACKET
3 - A/C COMPRESSOR
4 - BOLT (4)
24 - 52 PLUMBINGDR
A/C COMPRESSOR (Continued)