Chevrolet 70 1969 Series, Shop Manual

Page: 103 / 913

C A B A N D BO DY M O U N T IN G S 1-76
The oil may appear foamy which is normal.
To further check the compressor oil charge,
should previous check indicate insufficient oil, it
will be necessary to remove compressor from
vehicle.
R E P L A C IN G R E F R IG E R A T IO N S Y S T E M
C O M P O N E N T S O T H E R T H A N C O M P R E S S O R
When refrigerant system components other
than the compressor are replaced, the compressor
must also be removed and oil drained from the
compressor. The amount of oil to put back into the
compressor is found as follows: D O N O T add any
more oil than is necessary or maximum cooling
will be reduced.
1. Remove the compressor and place inahor-
izontal position with the compressor drain plug
downward, drain compressor in an empty grad­
uated bottle, measure the amount of oil and discard
this oil.
2. If the quantity of oil measured is more than
4 fluid ozs., replace into the compressor the same
amount of clean oil as the oil drained, plus the
following amount for the refrigeration system com­
ponent being changed.
a. Evaporator - 3 fluid ozs.
b. Condenser - 1 fluid oz.
c. Receiver-dehydrator assembly - 1 fluid oz.
Neglect any fluid oil coating loss in case of
line change.
3. If the oil quantity drained from the com ­
pressor is less than 4 ozs., replace into the com­
pressor 6 fluid ozs. of clean oil, plus the amount
shown previously for the respective component
replacements.
4. Replace compressor and system compon­
ents.
5. Evacuate, charge and perform operational
test.
CHECKING FOR LEAKS
Leak detector J-6084 as used for checking for
leaks in system, is a gas-operated torch-type leak
detector using a replaceable cylinder.
ASSEM BLING A N D LIG H T IN G T H E UNIT
1. Remove dust cap from cylinder.
2. Close valve knob on detector unit.
3. Thread detector unit onto top of fuel cylin­
der. Tighten finger tight.
4. Attach search hose assembly to detector
unit (fig. 15).
5. Open control valve until slight hiss of gas
is heard, then light gas at opening in chimney.
6. Adjust the flame until the desired volume
is obtained. A pale blue flame approximately 3 /8 ”
above the reaction plate is best for detecting leaks.
N O T E : The reaction plate will be heated to a
cherry red.
C O R R E C T IO N F O R Y E L L O W F L A M E
If the flame is yellow, insufficient air is being
inspirated or the reaction plate is dirty. Insuffic­
ient air may be caused by:
1. Obstructed or partially collapsed suction
tube.
2. Dirt or foreign substance in burner tube.
3. Dirty or partially clogged orifice.
Blowing air through the suction tube and back
through the detector will usually clear dirt or
foreign matter. If a yellow flame is caused by
dirty reaction plate, allow the flame to burn for
several minutes. This will usually burn the plate
clean. If an oxide film appears on the reaction
plate from continued use, it will reduce the sensi­
tivity of the detector. This may be remedied by
removing the plate and scraping the surface gently
with a knife.
T O C L E A N O R IF IC E
1. Never attempt to clean orifice by passing
anything through the hole.
C A U T IO N : Do not use lighted de­
tector in any place where combustible
or explosive gases, dusts or vapors
may be present.
Figure 15— Checking for Refrigerant Leak
CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L