Chrysler DODGE D150 1993 Service Manual page 1445

24 - 8 HEATING AND AIR CONDITIONING
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(e) If compressor clutch cycles 3 to 10 times per
minute with temperature between 20°C-32°C (68°F-
90°F), the cycling switch is normal. If the compressor
clutch fails to engage, check for continuity in the elec­
trical circuit. Above 32°C (90°F) the compressor clutch
may be continuously engaged (non-cycling) due to the
high heat load. This condition is normal.
(4) Refer to the Evaporator Heater Assembly for
the Removal/Installation procedures.
TESTING THE SYSTEM FOR LEAKS
If the air conditioning system is not cooling properly,
check that the refrigerant system is fully charged with
R-12. Follow the procedures in the Sight Glass Refrig­
erant Level Test section of this group.
If the refrigerant system is empty or low in refrig­
erant charge, a leak at any of the line fittings or
component seals is likely (Fig. 4 ) . To detect a leak in
the refrigerant system, perform one of the following
procedures as indicated by the symptoms.
ELECTRONIC
TEMPERATURE
CYCLING
SWITCH
EXPANSION
" H " VALVE
J9324-96
Fig. 4 Testing for Leaks
EMPTY REFRIGERANT SYSTEM LEAK TEST
(1) Evacuate the refrigerant system to the lowest
degree of vacuum possible.
(2) Prepare a 14 oz. refrigerant (R-12) charge to be
injected into the system.
(3) Connect and dispense 14 ozs. of refrigerant (R-
12) into the evacuated refrigerant system,
(4) Proceed to Step 2 of Low Refrigerant Level
Leak Test.
LOW REFRIGERANT LEVEL LEAK TEST
(1) Review the Safety Precautions section of this
group to determine if there is still R-12 in the refrig­
erant system.
(2) Position the vehicle in a breeze free work area
to make it less difficult to detect a small leak.
(3) With the engine not running, use an Electronic
Leak Detector, or equivalent, to search for leaks in
the most accessible areas first.
(a) Fittings, lines, or components that appear
oily usually will implicate a refrigerant leak.
(b) To inspect the evaporator core for leaks, it is
possible to insert the leak detector probe into the
opening on the right side of the instrument panel.
COMPRESSOR OIL LEVEL
It is important to have the correct amount of oil in
the A/C system to ensure proper lubrication of the
compressor. Too little oil will result in damage to the
compressor. Too much oil will reduce the cooling ca­
pacity of the system and consequently result in
higher discharge air temperatures.
To provide the desired balance for adequate lubri­
cation and cooling capacity, each compressor is
charged with 135 ml (4.6 oz.) of oil at the factory.
The oil used in the compressors is a 500 SUS vis­
cosity, wax-free refrigerant oil. Only refrigerant oil
of the same type should be used to service the sys­
tem. Do not use any other oil. The oil container
should be kept tightly capped until it is ready for
use, and then tightly capped after use to prevent en­
trance of dirt and moisture. Refrigerant oil will
quickly absorb any moisture it comes in contact with.
After the compressor has been installed and operated
in the A/C system, the oil will be distributed through­
out the system. Some of the oil will be trapped by com­
ponents in the system. An equivalent amount of oil
must be added to the system to compensate for the
trapped oil when replacing the following:
• Evaporator Coil: 59.2 ml (2 oz.)
• Condenser: 30 ml (1 oz.)
• Filter-Drier: 30 ml (1 oz.)
It will not be necessary to check oil level in the
compressor or to add oil unless there has been an oil
loss. Oil loss at a leak point will be evident by the
presence of a wet, shiny surface around the leak.
Replacement compressors are also charged with
135 ml (4.6 oz.). When replacing compressor; remove,
drain oil, measure amount and discard old oil. For
the replacement compressor use the same amount of
refrigerant oil as recovered from the failed compres­
sor. This adjustment is not needed if the system has
been flushed, removing retained oil.
The Compressor Oil Level Adjustment Chart
should be followed to determine the need to perform
an oil level adjustment.
Check oil level (basic fill) as follows:
(1) Slowly discharge complete system.
(2) With system discharged, disconnect suction and
discharge lines and remove compressor. Drain and dis­
card oil through suction port and discharge port on top.