Chrysler DODGE D150 1993 Service Manual page 1447

24 - 10 HEATING AND AIR CONDITIONING
•
(3) Add 50 ml (1.7 oz.) of clean refrigerant oil
through the suction port.
(4) Install compressor.
(5) Install the suction and discharge lines to the
compressor. Use new gaskets to prevent leakage.
Tighten the line nuts to 23 N*m (200 in. lbs.) torque.
(6) Evacuate and charge system.
OVER-ALL PERFORMANCE TEST
Humidity has an important bearing on the temper­
ature of the air delivered to the vehicle's interior.
This is true of all air conditioning systems It is im­
portant to understand the effect humidity has on the
performance of the system. When humidity is high,
the evaporator has to perform a double duty. It must
lower the air temperature and the temperature of the
moisture carried in the air. Condensing the moisture
in the air transfers a great deal of heat energy into
the evaporator fins and tubing. This reduces the
amount of heat the evaporator can absorb from the
air.
Evaporator capacity used to reduce the amount of
moisture in the air is not wasted. Wringing some of
the moisture out of the air entering the vehicle adds
to the comfort of the passengers. However, an owner
may expect too much from their air conditioning sys­
tem on humid days. A performance test is the best
way to determine whether or not the system is per­
forming up to standard. This test also provides valu­
able clues to the possible cause of trouble.
To perform the test the air temperature in the test
room must be 21°C (70°F) minimum.
(1) Connect a tachometer and manifold gauge set
(Fig. 5).
(2) Set A/C controls to MAX A/C, temperature le­
ver on full cool and blower on HIGH.
(3) Start engine and adjust rpm to 1,000 RPM with
A/C clutch engaged.
(4) Engine should be warmed up with doors, win­
dows and hood closed.
(5) Insert a thermometer in the left center A/C
outlet and operate the engine for 5 minutes. The A/C
clutch may cycle depending on ambient conditions.
(6) After 5 minutes note the discharge air temper­
ature. (If the clutch cycles take the reading before
the clutch disengages).
(7) Open the hood and disconnect the gray vacuum
line going to the heater water control valve. Observe
the valve a r m for movement as the line is discon­
nected. If it does not move refer to the heater valve
controls sections of this group. Plug the vacuum line
to prevent leakage.
(8) Operate the A/C for 2 more minutes and take
the discharge air temperature reading again. If the
temperature increased by more t h a n 2°C (5°F), check
LEFT SUCTION RIGHT
J 9 1 2 4 - 1 0 9
Fig. 5 Manifold Gauge Tester Connections
the blend air door cable for correct operation. If tem­
perature does not increase more t h a n 2°C (5°F), com­
pare discharge air temperature, suction and
discharge pressures with Performance Temperature
Chart. Connect the gray vacuum line.
(9) If the discharge air temperature fails to meet
the specifications in the Performance Temperature
Chart, refer to the diagnostic analysis charts for fur­
ther test information.