Inspection And Periodic Service; Compressor Oil; Pre-Delivery Inspection; Compressor Serial Number - Chevrolet 10 1971 Series Chassis Service Manual

HEATER AND AIR CONDITIONING 1A-16

COMPRESSOR OIL

Special refrigeration lubricant should be used in the
system. This oil is as free from moisture and con­
taminants as it is possible to attain by human processes.
This condition should be preserved by immediately cap­
ping the bottle when not in use.
See "Air Conditioning System Capacities" for the total
system oil capacity.
Due to the porosity of the refrigerant hoses and con­
nections, the system refrigerant level will show a definite
drop after a period of time. Since the compressor oil is
carried throughout the entire system mixed with the

PRE-DELIVERY INSPECTION

1. Check that engine exhaust is suitably ventilated.
2. Check the belt for proper tension.
3. With controls positioned for operation of the system,
operate the unit for ten minutes at approximately
2000 rpm. Observe the clutch pulley bolt to see that
the compressor is operating at the same speed as
the clutch pulley.
clutch slippage.
4. Before turning off the engine, check the sight glass
to see that the unit has a sufficient Refrigerant
charge. The glass should be clear, although during
milder weather it may show traces of bubbles. Foam
in the flow indicates a low charge. No liquid visible
and no temperature differential between compressor
inlet and outlet lines, indicates no charge.
5. Check refrigerant hose connections:
"O" ring Connections - Check torque of fittings as
charted later in this section under "Refrigerant Line
Connections;" retorque if required.
complete system.
Hose Clamp Connections - If clamp screw torque is
less than 10 in. lb., retighten to 20-25 in. lbs. Do
not tighten to new hose specifications or hose leakage
may occur. Leak test the complete system.
6. If there is evidence of an oil leak, check the com­
pressor to see that the oil charge is satisfactory.
A slight amount of oil leakage at the
NOTE:
compressor front seal is considered normal.
7. Check the system controls for proper operation.
6000 MILE INSPECTION
1. Check unit for any indication of a refrigerant leak.
2. If there is an indication of an oil leak, check the
compressor for proper oil charge.
A slight amount of oil leakage at the
NOTE:
compressor front seal is considered normal.
3. Check sight glass for proper charge of Refriger­
ant-12.
4. Tighten the compressor brace and support bolts and
check the belt tension.
5. Check refrigerant hose connections as in Step 5 of
"Pre-Delivery Inspection."
INSPECTION A N D PERIODIC SERVICE
Any speed variation indicates
Leak test the
refrigerant, a low refrigerant level will cause a danger­
ous lack of lubrication. Therefore the refrigerant charge
in the system has a definite tie-in with the amount of oil
found in the compressor and an insufficient charge may
eventually lead to an oil build-up in the evaporator.

COMPRESSOR SERIAL NUMBER

The compressor serial number is located on the serial
number plate on top of the compressor.
ber consists of a series of numbers and letters. This
serial number should be referenced on all forms and
correspondence related to the servicing of this part.
PERIODIC SERVICE
• Inspect condenser regularly to be sure that the fins
are not plugged with leaves or other foreign material.
• Check evaporator drain tubes regularly for dirt or
restrictions.
• At least once a year, check the system for proper
refrigerant charge and the flexible hoses for brittle­
ness, wear or leaks.
• Every miles check sight glass for low refrig­
6000
erant level.
• Check belt tension regularly.
INSTALLING CH ARG IN G STATION TO CHECK
SYSTEM OPERATION
1. Four Season System - The low pressure fitting is
located on the POA valve. The high pressure fitting
is located on the muffler (fig.
The connector assembly consists of in­
NOTE:
let (suction) and outlet (discharge) lines with the
freon hoses swaged to the metal lines (fig.
Roof-Mounted and GM Chevrolet Systems - The low
pressure fitting is located on the connector block and
the high pressure fitting on the muffler (fig.
Install Gauge Adapters
2.
high and low pressure gauge lines.
3. With the engine stopped, remove the caps from the
cored valve gauge fittings.
Be certain all valves on charging station are closed.
4.
Connect high pressure gauge line to high pressure
5.
gauge fitting.
See Figure Turn high pressure control
6. 22.
turn counter-clockwise (open).
pressure control (1) and allow refrigerant gas to hiss
from low pressure gauge line for three seconds,
then connect low pressure gauge line to low pres­
sure gauge fitting.
7. System is now ready for performance testing.
PERFORMANCE TEST
This test may be conducted to determine if the sys­
tem is performing in a satisfactory manner and should
be used as a guide by the serviceman in diagnosing
trouble within the system.
tions must be adhered to in order to make it possible to
The serial num­
25).
25).
25).
and onto the
J -5 4 2 0 J -9 4 5 9
one
(2)
Crack open low
The following fixed condi­
10-30 CHEVROLET TRUCK SERVICE MANUAL