1967 CHEVROLET CAMARO charging

HEATER
AND AIR
CONDITIONING
1A-13

AIR CONDITIONING

INDEX

Page

General Description
1A-13

Four-Season System
1A-13

Controls
1A-16

Comfortron System
. 1A-18

System Components
lA-19

Controls
1A-20

Universal System
. .
1A-21

Chevy
n
All-Weather System
•
1A-21

Corvette Four-Season System
. 1A-22

General Information
. . . 1A-26

Precautions
in
Handling R-12
1A-26

Precautions
in
Handling Refrigerant Lines
1A-28

Maintaining Chemical Stability
in the

Refrigeration System
1A-28

Gauge
Set 1A-29

Charging Station
IA-29

Leak Testing
the
System
1A-29

Vacuum Pump
1A-30

Availability
of
Refrigerant-12
. . 1A-30

Compressor
Oil 1A-31

Compressor Serial Number
1A-31

Inspection
and
Periodic Service
1A-31

Pre-Delivery Inspection
1A-31

6,000 Mile Inspection
1A-32

Periodic Service
, 1A-32

Installing Gauge
Set to
Check System Operation
....
1A-32

Performance Test
1A-32

Performance Data lA-r33

Comfortron System Operational Test
1A-33

Chevrolet Comfortron Tester
1A-34

Complete System Checks
1A-35

Maintenance
and
Adjustments ......
1A-37

Evaporator Comtrol Valve (POA)
.
1A-37
Page

Thermostatic Switch
1A-37

Expansion Valve
1A-41

Engine Idle Compensator
. . .
1A-42

Evacuating
and
Charging Procedures
1A-42

Purging
the
System
1A-42

Evacuating
and
Charging
the
System
1A-43

Checking
Oil . 1A-43

Component Replacement
and
Minor Repair
1A-45

Refrigerant Line Connections
1A-45

Repair
of
Refrigerant Leaks
1A-46

Preparing System
for
Replacement
of

Component Parts
. 1A-46

Foreign Material
in the
System
.
1A-47

Condenser
.
1A-48

Receiver-Dehydrator
1A-48

Evaporator
1A-49

Expansion Valve
1A-57

Evaporator Control Valve (POA)
1A-59

Thermostatic Switch
or
Blower Switch
. .
1A-59

All Weather-Pull Cable
1A-61

Blower Assembly
1A-62

Air Inlet Valve
.
1A-64

Blower
and
Evaporator Assembly
1A-64

Air Distributor Assembly
and
Outlet Ducts ...... 1A-64

Comfortron Automatic Control Components
1A-66

Collision Procedure lA-70

Four-Season Heater Components
1A-73

Comfortron Heater Components
. . . 1A-75

Compressor
1A-76

Wiring Diagrams
1A-78

Special Tools
.
1A-84

GENERAL DESCRIPTION

Four
air
conditioning systems
are
covered
in
this

section. They are:

1.
The
Four-Season System (Chevrolet, Chevelle,

Camaro and Corvette).

2.
The Comfortron System (Chevrolet).

3.
The All Weather System (Chevy n).

4.
The Universal System (Chevrolet, Chevelle, Chevy
n,

Camaro)

Underhood components (that
is, the
compressor,
con-

denser
and
receiver-dehydrator)
are
much
the
same
in

type,
location
and
method
of
attachment
on all of
the

above systems. The six-cylinder reciprocating compres-

sor
is
bracket-mounted
to the
engine
and
belt driven

from
the
crankshaft pulley.
The
condenser
is
mounted

ahead
of the
engine cooling radiator
and the
receiver-

dehydrator
is
mounted
in
the refrigerant line downstream

of
the
condenser.
All
cooling system components
are

connected by means
of
flexible refrigerant lines.

Evaporator size
and
location differ from system
to

system
as do
methods
of
temperature control
and air

supply
and
distribution.

FOUR-SEASON SYSTEM

The Four-Season system used
in the
Chevrolet,

Chevelle, Camaro,
and
Corvette vehicles
may be
iden-

tified
by the
fact that
it
uses
an
evaporator pressure

control known
as the POA
(Pressure Operated Absolute)

suction throttling valve.
Both
the
heating
and
cooling functions
are
performed

by this system.
Air
entering
the
vehicle must pass

through
the
cooling unit (evaporator)
and
through
(or

around)
the
heating unit,
in
that order, and the system
is

thus referred to
as a
''reheat" system.

The evaporator provides maximum cooling
of the air

passing through
the
core when
the air
conditioning sys-

tem
is
calling
for
cooling.
The
control valve acts in the

system only
to
control
the
evaporator pressure
so
that

minimum possible temperature
is
achieved without core

freeze-up.
The
valve
is
preset,
has no
manual con-

trol,
is
automatically altitude compensated,
and non-

repairable.

The heater core will be hot
at
all times since no water

valve
is
present
in
the system.

System operation
is as
follows (See Figure 24 and 25):

Air, either outside
air or
recirculated
air
enters
the

system
and is
forced through
the
system by the blower.

As
the air
passes through
the
evaporator core,
it

receives maximum cooling
if
the
air
conditioning controls

are calling
for
cooling. After leaving
the
evaporator,

the
air
enters
the
Heater
and Air
Conditioner Selector

Duct Assembly where,
by
means
of
manually operated

diverter doors,
it is
caused
to
pass through
or to
bypass

the heater core
in the
proportions necessary
to
provide

the desired outlet temperature. Conditioned airflow then

enters
the
vehicle through either
the
floor distributor

duct
or the
dash outlets. Remember that the heater core

CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-26

clockwise for medium and high blower speed, as

desired. Low blower speed is automatic during

cooling operations.

4.
"Def-Pull". This knob should be pushed fully in.

Additional Cooling Hints

1.
The center barrel outlet in the dash may be rotated

to deflect air as desired or used to act as a shut off

door.

2.
The right and left ball outlets may be rotated to

deflect air in the direction desired. Each outlet has

a shut off valve operated by a knob approximately

4 in. inboard. When the knob is horizontal, the valve

is open.

3.
There are two (2) additional outlets in the bottom of

the ducts approximately 6" inboard from the valve

knobs. A rotating cover will open these outlets to

provide cool air for the feet if desired.

4.
When first entering a very warm car, open the

windows for a few minutes until the interior of the

car has cooled off.
Heating

1.
"Air Pull-Fan". Pull this knob fully out. Rotate

the knob clockwise for low, medium or high blower

speed as desired. If just a small amount of heat is

desired, leave the fan on low or medium speed and

regulate the temperature with the "Cool In-Hot Pull"

knob.

2.
"Air Cond-Pull". This knob should normally be

pushed fully in. However, during cool, damp days

it is possible, by pulling this knob fully out, to de-

humidify the air by passing it through the evaporator

core before reheating to the desired outlet

temperature.

3.
"Cool In-Hot Pull". Pull this knob out as far as

necessary to provide the temperature desired.

4.
"Def-Pull". Pull this knob all the way out for

maximum defrosting or de-icing. When the knob is

partly out, a portion of the hot air is used for de-

frosting and the balance is discharged through the

heater outlet.

GENERAL INFORMATION

In any vocation or trade, there are established proce-

dures and practices that have been developed after many

years of experience. In addition, occupational hazards

may be present that require the observation of certain

precautions or use of special tools and equipment. Ob-

serving the procedures, practices and precautions of

servicing refrigeration equipment will greatly reduce the

possibilities of damage to the customers' equipment as

well as virtually eliminate the element of hazard to the

serviceman.

PRECAUTIONS IN HANDLING REFRIGERANT-12

Refrigerant-12 is transparent and colorless in both the

gaseous and liquid state. It has a boiling point of 21.7^

below zero and, therefore, at all normal temperatures

and pressures it will be a vapor. The vapor is heavier

than air and is noninflammable, nonexplosive, non-

poisonous (except when in contact with an open flame)

and noncorrosive (except when in contact with water).

The following precautions in handling R-12 should be

observed at all times.

• All refrigerant drums are shipped with a heavy metal

screw cap. The purpose of the cap is to protect the

valve and safety plug from damage. It is good .prac-

tice to replace the cap after each use of the drum.

• If it is ever necessary to transport or carry a drum

or can of refrigerant in a car, keep it in the luggage

compartment. Refrigerant should not be exposed to

the radiant heat from the sun for the resulting in-

crease in pressure may cause the safety plug to

release or the drum or can to burst..

• Drums or disposable cans should never be subjected

to high temperature when adding refrigerant to the

system. In most instances, heating the drum or can

is required to raise the pressure in the container

higher than the pressure in the system during the

operation. It would be unwise to place the drum on a

gas stove, radiator or use a blow torch while pre-

paring for the charging operation, for a serious ac-

cident can result. Don't depend on the safety
plug - many drums have burst when the safety plug

failed.' Remember, high pressure means that great

forces are being exerted against the walls of the

container. A bucket of warm water, not over 125°F,

or warm wet rags around the container is all the heat

that is required.

• Do not weld or steam clean on or near the system.

Welding or steam cleaning can result in a dangerous

pressure buildup in the system.

• When filling a small drum from a large one, never

fill the drum completely. Space should always be

allowed above the liquid for expansion. If the drum

were completely full and the temperature was in-

creased, hydraulic pressure with its tremendous

force would result.

• Discharging large quantities of R-12 into a room can

usually be done safely as the vapor would produce

no ill effects, however, in the event of an accidental

rapid discharge of the system it is recommended

that inhalation of large quantities of R-12 be avoided.

This caution is especially important if the area con-

tains a flame producing device such as a gas heater.

While R-12 normally is nonpoisonous, heavy con-

centrations.. of it in contact with a live flame will

produce a toxic gas. The same gas will also attack

all bright metal surfaces.

• Protection of the eyes is of vital importance! When

working around a refrigerating system, an accident

may cause liquid refrigerant to hit the face. If the

eyes are protected with goggles or glasses, no

serious damage can result. Just remember, any

R-12 liquid that you can touch or that touches you is

at least 21.7"F. below zero. The eyeballs can't take

much of this temperature. If R-12 liquid should

strike the eyeballs, here is what to do:

1.
Keep calm.

2.
Do not rub the eyes! Splash the affected area with

quantities of cold water to gradually get the tem-

perature above the freezing point. The use of min-

eral, cod liver or an antiseptic oil is important in

CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-29

time as possible will be required to perform the

operation. Don't leave the system open any longer

than is necessary.

• Finally, after the operation has been completed and

the system sealed again, air and moisture should be

evacuated from the system before recharging.

GAUGE SET

The gauge set (fig. 41) is used when purging, evacua-

ting, charging or diagnosing trouble in the system. The

gauge at the left is known as the low pressure gauge.

The face is graduated into pounds of pressure and, in

the opposite direction, in inches of vacuum. This is the

gauge that should always be used in checking pressures

on the low pressure side of the system. When all parts of

the system are functioning properly the refrigerant

pressure on the low pressure side never fails below 0

pounds pressure. However, several abnormal conditions

can occur that will cause the low pressure to fall into a

partial vacuum. Therefore, a low pressure gauge is

required.

The high pressure gauge is used for checking pres-

sures on the high pressure side of the system.

The connection at the left is for attaching the low

pressure gauge line and the one at the right the high

pressure gauge line. The center connector is common to

both and is for the purpose of attaching a line for adding

refrigerant, discharging refrigerant, evacuating the sys-

tem and other uses. When not required, this line or

connection should be capped.

NOTE:
Gauge fitting connections should be in-

stalled hand tight only and the connections leak

tested before proceeding.

The hand shutoff valves on the gauge manifold do not

control the opening or closing off of pressure to the

gauges. They merely close each opening to the center

connector and to each other. During most diagnosing

and service operation, the valves must be closed. The

only occasion for opening both at the same time would be

to bypass refrigerant vapor from the high pressure to

the low pressure side of the system, or in evacuating

both sides of the system.

CHARGING STATION

The J-8393 Charging Station is a portable assembly of

a vacuum pump, refrigerant supply, gauges, valves, and

most important, a five (5) pound metering refrigerant

charging cylinder. The use of a charging ey'inder elim-

inates the need for scales, hot water pails, etc.

The chief advantage of this unit is savings. A very

definite savings in refrigerant and time can be obtained

by using this unit. Since the refrigerant is metered into

the system by volume, the correct amount may be added

to.
the system and charged to the customer. This, coupled

with the fact that the unit remains "plumbed" at all times

and thus eliminates loss of refrigerant in purging of

lines and hooking-up, combines to enable the operator to

get full use of all refrigerant purchased by the

dealership.

All evacuation and charging equipment is hooked to-

gether in a compact portable unit (fig. 42) which brings

air conditioning service down to the basic problem of

hooking on two hoses, and manipulating clearly labeled

valves.
Fig.
42—System Charging Station

This will tend to insure that the job will be done without

skipping operations. As a result, you can expect to save

time and get higher quality work, less chance of an over

or undercharge, or comeback.

The pump mount is such that the dealer may use his

own vacuum pump. The gauges and manifold are in com-

mon use. Thus a current air conditioning dealer can use

the equipment on hand and avoid duplication.

LEAK TESTING THE SYSTEM

Whenever a refrigerant leak is suspected in the system

or a service operation performed which results in dis-

turbing lines or connections, it is advisable to test for

leaks.
Common sense should be the governing factor in

performing any leak test, since the necessity and extent

of any such test will, in general, depend upon the nature

of the complaint and the type of service performed on

the system. It is better to test and be sure, if in doubt,

than to risk the possibility of having to do the job over

again.

NOTE:
The use of a leak detecting dye within

the system is not recommended because of the

following reasons:

1.
Refrigerant leakage can exist without any oil leakage.

In this case the dye will not indicate the leak, how-

ever, a torch detector will.

2.
The addition of additives, other than inhibitors, may

alter the stability of the refrigeration system and

cause malfunctions.

3.
Dye type leak detectors which are insoluble form a

curdle which can block the inlet screen of the ex-

pansion valve.

CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-30

Leak Detector

Tool J-6084 (fig. 43) is a propane gas-burning torch

which is used to locate a leak in any part of the system.

Refrigerant gas drawn into the sampling tube attached to

the torch will cause the torch flame to change color in

proportion to the size of the leak. Propane gas fuel

cylinders used with the torch are readily available

commercially throughout the country.

CAUTION: Do not use lighted detector in any

place where combustible or explosive gases,

dusts or vapors may be present;

Operating Detector

1.
Open control valve only until a low hiss of gas is

heard, then light gas at opening in chimney.

2.
Adjust flame until desired volume is obtained. This

is most satisfactory when blue flame is approxi-

mately 3/8" above reactor plate. The reaction plate

will quickly heat to a cherry red.

3.
Explore for leaks by moving the end of the sampling

hose around possible leak points in the system. Do

not pinch or kink hose.

NOTE: Since R-12 is heavier than air, it is

good practice to place open end of sampling tube

immediately below point being tested, partic-

ularly in cases of small leaks.

CAUTION: Do not breathe the fumes that are

produced by the burning of R-12 gas in the de-

tector flame, since such fumes can be toxic in

large concentrations of R?»12.

4.
Watch for color changes. The color of the flame

which passes through the reaction plate will change

to yellow when sampling hose draws in very small

CHIMNEY

REACTION PLATE

BURNER HEAD

Fig.
43—Leak Detector
leaks of R-12. Large leaks will be indicated by a

change in color to a vivid purplish-blue. When the

sampling hose passes the leak, the flame will clear

to an almost colorless pale-blue again. If the flame

remains yellow when unit is removed from leak,

insufficient air is being drawn in or the reaction

plate is dirty.

NOTE: A refrigerant leak in the high pressure

side of the system may be more easily detected

when, if possible, the system is in operation. A

leak on the low pressure side may be most

easily detected after the engine has been shut

off for several minutes to allow system pres-

sures to equalize. This particularly applies to

the front seal.

VACUUM PUMP

A vacuum pump should be used for evacuating air and

moisture from the air conditioning system.

Vacuum pump, Tool J-5428, (fig.. 44) is available for

this purpose. It is used as a component part of the

Charging Station J-8393, described previously. The fol-

lowing precautions should be observed relative to tbe

operation and maintenance of this pump.

' • Make sure dust cap on discharge outlet of vacuum

pump is removed before operating.

• Keep all openings capped when not in use to avoid

moisture being drawn into the system.

• Oil should be changed after every 250 hours of nor-

mal operation.

To change oil, simply unscrew hex nut located on

back side of pump, tilt backward and drain out oil

(fig. 44). Recharge with 8 ounces of vacuum pump

oil.
If you desire to flush out the pump, use this

same type clean oil. Do not use solvent.

NOTE: Improper lubrication will shorten the

life of pump.

• If this pump is subjected to extreme or prolonged

cold, allow it to remain indoors until oil has reached

approximate room temperature. Failure to warm oil

will result in a blown fuse.

• A five ampere time delay cartridge fuse has been

installed in the common line to protect the windings

of the compressor. The fuse will blow if an ex-

cessive load is placed on the pump. In the event the

fuse is blown, replace with a five ampere time delay

fuse - do not use a substitute fuse as it will result in

damage to the starting windings.

• If the pump is being utilized to evacuate a burnt-out

system, a filter must be connected to the intake

fitting to prevent any sludge from contaminating the

working parts, which will result in malfunction of the

pump.

• Do not use the vacuum pump as an air compressor.

AVAILABILITY OF REFRIGERANT-12

Refrigerant-12 is available through Parts Stock in 25

lb.
drums and in 15 oz. disposable cans. Valves are

available for
the"
disposable cans, which may be used as

individual cans or as a group of up to four cans (fig. 45).

Tool J-6272 is used with one through four cans. The

use of the four-can fixture makes it possible to charge

the system with a known quantity of refrigerant without

CHEVROLET CHASSIS SERVICE MANUAL

HEATER
AND AIR
CONDITIONING
1A-31

FIVE
AMP

TIME DELAY

FUSE

CORD
TO

110
AC
SOURCE
PUMP

INLET
PUMP DISCHARGE

OUTLET

Fig.
44—Vacuum Pump

the use of weighing equipment necessary with the larger

drum. The single can Valve J-6271 can be used for com-

pleting the charge and for miscellaneous operations such
Fig.
45-R-12 Disposable Cans

as flushing. The valves are installed by piercing the top

seal of the cans.

Evacuating and charging procedures later in this sec-

tion will make use of the J-8393 Charging Station which

uses the 25 lb. drum of refrigerant.

COMPRESSOR OIL

Special refrigeration lubricant should be used in the

system. It is available in 1 quart graduated bottles

through Parts Stock. This oil is as free from moisture

and contaminants as it is possible to attain by commercial

processes. This condition should be preserved by im-

mediately capping 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

refrigerant a low refrigerant level will cause a dangerous

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. The serial num-

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.

INSPECTION AND PERIODIC SERVICE

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

compressor is operating at the same speed as the
clutch pulley. Any speed variation indicates clutch

slippage.

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

indicates no charge.

CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-32

5.
Check hose clamp connections. If clamp screw torque

is less than 10 lb. in., retighten to 20-25 lb. in. Do

not tighten to new hose specifications or hose leak-

age may occur.

6. If there is evidence of an oil leak, check the com-

pressor to see that the oil charge is satisfactory.

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 proper oil charge.

3.
Check sight glass for proper charge of Refrigerant-

12.

4.
Tighten the compressor brace and support bolts and

check the belt tension.

5.
Check hose clamp connections as in step 5 above.

6. Check thermostatic switch setting (Universal and

All-Weather Systems.)

PERIODIC SERVICE

• Inspect condenser regularly to be sure that it is not

plugged with leaves or other foreign material.

Fig.
46—Compressor Connector Block—Typical
• 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 6000 miles check sight glass for low refriger-

ant level.

• Check belt tension regularly.

• Every week - during winter months or other periods

when the system is not being operated regularly- run

the system, set for maximum cooling, for 10 or 15

minutes to insure proper lubrication of seals and

moving parts.

INSTALLING GAUGE SET TO CHECK

SYSTEM OPERATION

Compressor Suction and Discharge Connector

Compressor connector assemblies used on all vehicles

are of the same basic design consisting of the inlet

(suction) and outlet (discharge) connections, gauge fittings

and muffler and, in general, the assemblies differ only in

the location of the gauge fittings.

On Universal and Four-Season Systems the outlet line

extends along side of and toward the front of the com-

pressor and the muffler in the line is bracket mounted to

the compressor body. In all Universal Systems the gauge

fittings for both low and high pressure sides of the sys-

tem are located in the connector body. On Four-Season

Systems the high pressure gauge fitting is located on the

muffler and the low pressure gauge fitting is on the POA

Valve.

The Chevy n All-Weather System compressor con-

nector assembly is similar to the Universal System

connector assembly described above except that the

muffler extends straight out from the connector and

is not bracket mounted to the compressor.

Universal and Chevy II All-Weather System

1.
Install Gauge Adapter (J-5420 or J-9459) onto the

high and low pressure hoses of the gauge set.

2.
With the engine stopped, remove the caps from the

cored valve gauge, connectors on the compressor

fittings block.

3.
Connect the gauge lines with adapters to the threaded

connectors on the compressor fittings block.

Four-Season and Comfortron Systems

Installation of the gauge set onto the Four-Season and

Comfortron systems is accomplished in the same manner

as outlined above except that system performance checks

must be performed with the low pressure hose line and

adapter attached to the fitting on the POA valve. Charging

procedures should be performed with the high pressure

gauge line connected to the high pressure gauge fitting

located on the outlet line muffler and the low pressure

gauge line attached to the POA fitting.

CAUTION: When removing gauge lines from

the compressor fittings block be sure to remove

the adapters from the fittings rather than the

gauge lines from the adapters.

PERFORMANCE TEST

This test may be conducted to determine if the system

is performing in a satisfactory manner and should be

used as a guide by the serviceman in diagnosing trouble

CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-42

EXTERNAL

EQUALIZER LINE

Fig. 54—Thermosratic Switch Adjustment

POORLY LOCATED POWER ELEMENT BULB

Normal Pressure.

Poor Cooling.

ENGINE IDLE COMPENSATOR

This additional aid to prevent stalling during prolonged

hot weather periods is included with all air conditioned

vehicles. The idle compensator is a thermostatically

controlled air bleed which supplies additional air to the

idle mixture. On V-8 engines, with factory installed air
Fig. 55—Expansion Valve

conditioning systems, the compensator is located within

the carburetor and is accessible when the engine air

cleaner is removed. On all other vehicles the compen-

sator is threaded into a manifold, fitting below the

carburetor. All compensators are factory set and are

non-adjustable. A malfunctioning unit should be replaced.

NOTE:
If engine idle is erratic, hold the idle

compensator valve closed with a pencil or

wooden dowel while adjusting the idle mixture

screw(s). Never attempt to bend the bimetal

strip or attempt any valve adjustment.

EVACUATING AND CHARGING PROCEDURES

1967 AIR CONDITIONING SYSTEM CAPACITIES

Four-Season Systems (Chevrolet and Chevelle)

Universal System (Chevrolet, Chevelle and Camaro)

Universal and All-Weather System (Chevy II)
Refrigerant Charge

3 lbs., 12 oz.

3 lbs.

2 lbs., 8 oz.
Oil Charge

11 ozs. 525 viscosity

11 ozs. 525 viscosity

11 ozs. 525 viscosity

PURGING THE SYSTEM

In replacing any of the air conditioning components the

system must be completely purged or drained of re-

frigerant. The purpose is to lower the pressure inside

the system so that a component part can be safely

removed.

1.
With engine stopped install high and low pressure

lines of gauge set to the proper high and low pres-

sure gauge fittings (see "Installing Gauge Set to

Check Operation").
2.
With plug removed from the centerline on the gauge

manifold, open high pressure gauge valve and dis-

charge the vapor slowly through the center

connection.

CAUTION: Do

compressor

refrigerant.
not open valves too much or

oil may be discharged with the

A rag wrapped around the end of

the center gauge line will prevent the splashing

of oil in the event of accidental rapid discharge.

CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-43

LOW PRESSURE

CONTROL
HIGH PRESSURE

CONTROL

3

VACUUM

CONTROL
4

FREON

CONTROL

Fig,
56—Charging Station Controls

3.
When the pressure is reduced to below 100 pounds

on the high pressure gauge, open the low pressure

gauge valve and continue discharging until all re-

frigerant has been released. Close both gauge valves.

EVACUATING AND CHARGING THE SYSTEM

GENERAL NOTE: La all evacuating procedures

shown below, the specification of 26-28 inches

of Mercury vacuum is used. These figures are

only attainable at or near Sea Level Elevation.

For each 1000 feet above sea level where this

operation is being performed, the specifications

should be lowered by 1 inch. Example: at 5000

ft. elevation, only 21 to 23 inches of vacuum can

normally be obtained.

Whenever the air conditioning system is open for any

reason, it should not be put into operation again until it

has been evacuated to remove air and moisture which

may have entered the system.

The following procedures are based on the use of the

J-8393 Charging Station.

Filling Charging Cylinder

1.
Open control valve on refrigerant drum.

2.
Open valve on bottom of charging cylinder allowing

refrigerant to enter cylinder.

3.
Bleed cylinder valve on top (behind control panel) as

required to allow refrigerant to enter. When re-

frigerant reaches desired level (see "Air Condition-

ing System Capacities"), close valve at bottom of

cylinder and be certain bleed valve is closed

securely.

NOTE: It will be necessary to close bleed valve

periodically to allow boiling to subside to check

level in sight glass.

Installing Charging Station to System

1.
Be certain all valves on charging station are closed.

2.
Connect high pressure gauge line to high pressure

gauge fitting. (See "Installing Gauge Set to Check

System Operations.")
3.
See Figure 56. Turn high pressure control (2) one

turn counter-clockwise (open). Crack open low pres-

sure control (1) and allow refrigerant gas to hiss

from low pressure gauge line for three seconds,

then connect low pressure gauge line to low pressure

gauge fitting.

4.
System is now ready for performance testing.

Evacuating and Charging System

1.
Install charging station as previously described.

Refer to Figure 56 and 57 while performing the

following operation.

2.
Remove Low Pressure gauge line from compressor.

3.
Crack open high (2) and low (1) pressure control

valves, and allow refrigerant gas to purge from

system. Purge slow enough so that oil does not

escape from system along with Refrigerant.

4.
When refrigerant flow stops, connect Low Pressure

gauge line to compressor.

5.
Turn on vacuum pump and open Vacuum Control

Valve (3).

6. With system purged as above, run pump until 28-29

inched of vacuum is obtained. Continue to run pump

for 15 minutes after the system reaches 28-29 inches

vacuum.

7.
If 28-29 inches cannot be obtained, close Vacuum

Control Valve (3) and shut off vacuum pump. Open

Refrigerant Control Valve (4) and allow 1/2 pound of

R-12 to enter system. Locate and repair all leaks.

8. After evacuating for 15 minutes, add 1/2 pound of

R-12 to system as described in Step 7 above. Purge

this 1/2 pound and reevacuate for 5 minutes. This

second evacuation is to be certain that as much con-

tamination is removed from the system as possible.

9. Only after evacuating as above, system is ready for

charging. Note reading on sight glass of charging

cylinder. If it does not contain a sufficient amount

for a full charge, fill to the proper leveL

10.
With High and Low pressure Valves (1 and 2) open,

close Vacuum Control Valve (3) and open Freon

Control Valve (4). Operating the heater and air

conditioner blower with the controls set for cooling

will help complete the charging operation.

NOTE: If the charge will not transfer com-

pletely from the station to the system, close

the high pressure valve at the gauge set, set

the air conditioning controls for cooling, check

that the engine compartment is clear of ob-

structions, and start the engine. Compressor

operation will decrease the low side pressure

in the system.

System is now charged and should be performance

tested before removing gauges.

CHECKING OIL

In the six cylinder compressor it is not recommended

that the oil be checked as a matter of course. Gener-

ally, compressor oil level should be checked only where

there is evidence of a major loss of system oil such as

might be caused by:

• A broken refrigerant hose.

• A severe hose fitting leak.

CHEVROLET CHASSIS SERVICE MANUAL