1967 CHEVROLET CAMARO oil temperature

LUBRICATION 0-13

LUBRICATION

INDEX

Page

Engine Crankcase Oil . 0-13

Crankcase Capacities. . 0-13

Lubrication . ,
•
o-13

SAE Viscosity Oils 0-13

Types of Oils 0-14

Maintaining Oil Level 0-14

Oil and Filter Change Intervals 0-14

Oil.
. . ...:.. 0-14

Filter o-14

Crankcase Dilution . 0-14

Automatic Control Devices to Minimize

Crankcase Dilution 0-14

Crankcase Breather Cap 0-14

Crankcase Ventilation System 0-15

Valve Type 0-15

Fuel Filter 0-15

Air Cleaner . 0-15

Polyurethane Type 0-15

Oil Wetted Paper Element Type 0-15

Battery Terminal Washers 0-15
Page

Distributor 0-15

Rear Axle and 3-Speed and Overdrive

4-Speed Transmission 0-15

Recommended Lubricants 0-15

Multi-Purpose Gear Lubricants 0-15

Lubricant Additions 0-15

Lubricant Changes 0-15

Powerglide Transmission 0-15

Turbo Hydra-Matic 0-16

Front Wheel Bearings 0-16

Manual Steering Gear . . . . 0-16

Power Steering 0-16

Air Conditioning 0-16

Brake Master Cylinder. 0-16

Parking Brake 0-16

Clutch Cross-Shaft , 0-16

Chassis Lubrication 0-16

Lubrication Diagrams . . 0-19

Body Lubrication (Chevrolet, Chevelle, Chevy n, Camaro). 0-20

Body Lubrication Points (Corvette) . 0-21

The selection of the proper lubricant and its correct

application at regular intervals does much to increase the

life and operation of all moving parts of the vehicle.

Consequently, it is important that the correct grade of

oil or grease, as noted in the following pages, be used.

ENGINE CRANKCASE OIL

Crankcase Capacity

4 Cylinder 4 qt.

6 Cylinder 4 qt.

8 Cylinder (283) 4 qt.

8 Cylinder (327) 4 qt.

8 Cylinder (350) 4 qt.

8 Cylinder (396) 4 qt.

8 Cylinder (427) Chevrolet 4 qt.

8 Cylinder (427) Corvette 5 qt.

For 4 Cyl. Add .5 qt. with filter change;

1 qt. for 6 and 8 Cyl. engines.

Lubrication

Crankcase oil should be selected to give the best per-

formance under the climatic and driving conditions in the

territory in which the vehicle is driven.

During warm or hot weather, an oil which will provide

adequate lubrication under high operating temperatures

is required.

During the colder months of the year* an oil which will

permit easy starting at the lowest atmospheric tempera-

ture likely to be encountered, should be used.

When the crankcase is drained and refilled, the crank-

case oil should be selected, not on the basis of the exist-

ing temperature at the time of the change, but on the

lowest temperature anticipated for the period during

which the oil is to be used.

Unless the crankcase oil is selected on the basis of

viscosity or fluidity of the anticipated temperature, dif-

ficulty in starting will be experienced at each sudden

drop in temperature.
SAE Viscosity Oils

SAE Viscosity Numbers indicate only the viscosity or

body of the oil, that is, whether an oil is a light or a

heavy body oil, and do not consider or include other

properties or quality factors.

The lower SAE Viscosity Numbers, such as SAE 5W

and SAE 10W which represent the light body oils, are

recommended for use during cold weather to provide

easy starting and instant lubrication. The higher SAE

Viscosity Numbers such as SAE 20 and SAE 20W, which

represents heavier body oils, are recommended for use

during warm or hot weather to provide improved oil

economy and adequate lubrication under high operating

temperatures.

Oils are available which are designed to combine the

easy starting characteristics of the lower SAE Viscosity

Number with the warm weather operating characteristics

of the higher SAE Viscosity Number. These are termed

"multi-viscosity oils," SAE 5-10W, SAE 5W-20, SAE

10W-20W, and SAE 10W-30.

The following chart will serve as a guide for the

selection of the correct SAE Viscosity Number for use

under different atmospheric temperature ranges, and

suggests the appropriate SAE Viscosity Numbers when

multi-viscosity oils are used.

Lowest Anticipated

Temperature

During Time

Oil Will Be

in Crankcase

32°F.

0°F.

Below 0°F.
Recommended

SAE Viscosity

Oils

SAE 20 or 20W

SAE 10W

SAE 5W
Recommended

SAE

Multi-

Viscosity

Oils

SAE 10W-30 .

SAE 10W-30

SAE 5W-20

SAE 30 or 10W-30 is recommended when most of the

driving is at high speeds and/or at temperatures above

90
°F.

CHEVROLET CHASSIS SERVICE MANUAL

LUBRICATION 0-14

SAE 5W-30 oils may be used during periods when

temperatures of 32° and below are to be expected.

Types of Oils

In service, crankcase oils may form sludge and varnish

and under some conditions, corrosive acids unless pro-

tected against oxidation.

To minimize the formation of these harmful products

and to assure the use of oil best suited for present day

operating conditions, automobile manufacturers have de-

veloped a series of sequence tests designed to evaluate

the ability of any oil to properly lubricate automobile

engines.

It is recommended that only those oils which are

certified by their suppliers as meeting or exceeding the

maximum severity requirements of these sequence tests

(or GM Standard 4745-M) be used in Chevrolet engines.

Certified sequence tested oils will be described as such

on their containers.

Maintaining Oil Level

The oil gauge rod is marked "Full" and "Add Oil."

These notations have broad arrows pointing to the level

lines.
The oil level should be maintained between the

two lines, neither going above the "Full" line nor under

the "Add Oil" line. DO NOT OVERFILL. After operating

vehicle allow a few minutes for oil to return to crankcase

before checking oil level.

Check the oil level frequently and add oil when

necessary.

Oil and Filter Change Intervals

NOTE:
Under prolonged dusty driving condi-

tions,
it is recommended that these operations

be performed more often.

OIL

To insure continuation of best performance, low main-

tenance cost and long engine life, it is necessary to

change the crankcase oil whenever it becomes contami-

nated with harmful foreign materials. Under normal

driving conditions draining the crankcase and refilling

with fresh oil every 60 days or every 6000 miles which-

ever occurs first, is recommended.

It is always advisable to drain the crankcase only after

the engine has become thoroughly warmed up or reached

normal operating temperature. The benefit of draining is,

to a large extent, lost if the crankcase is drained when

the engine is cold, as some of the suspended foreign

material will cling to the sides of the oil pan and will not

drain out readily with the cold, slower moving oil.

OIL FILTER

Change engine oil filter every 6000 miles or every 6

months, whichever occurs first.

NOTE:
For Vehicles in heavy duty operation

involving continuous start-stop or prolonged idl-

ing, engine oil should be changed after 2500-

3000 miles of operation. The filter should be

changed after 5000-6000 miles of operation.
Crankcase Dilution

Probably the most serious phase of engine oil deterio-

ration is that of crankcase dilution which is the thinning

of the oil by fuel vapor leaking by pistons and rings and

mixing with the oil and by condensation of water on the

cylinder walls and crankcase.

Leakage of fuel, or fuel vapors, into the oil pan occurs

mostly during the "warming up" period when the fuel is

not thoroughly vaporized and burned. Water vapor enters

the crankcase through normal engine ventilation and

through exhaust gas blow-by. When the engine is not

completely warmed up, these vapors condense, combine

with the condensed fuel and exhaust gases and form acid

compounds in the crankcase.

As long as the gases and internal walls of the crank-

case are hot enough to keep water vapor from con-

densing, no harm will result. However, when the engine

is run in low temperatures moisture will collect and

unite with the gases formed by combustion resulting in

an acid formation. The acid thus formed is likely to

cause serious etching or pitting which will manifest itself

in excessively rapid wear on piston pins, camshaft

bearings and other moving parts of the engine, oftentimes

causing the owner to blame the car manufacturer or the

lubricating oil when in reality the trouble may be traced

back to the character of fuel used, or a condition of the

engine such as excessive blowby or improper carburetor

adjustment.

Automatic Control Devices to Minimize

Crankcase Dilution

All engines are equipped with automatic devices which

aid greatly in minimizing the danger of crankcase

dUution.

The thermostat, mounted in the cylinder head water

outlet, restricts the flow of water to the radiator until a

predetermined temperature is reached, thus minimizing

the length of time required to reach efficient operating

temperature, reducing the time that engine temperatures

are conducive to vapor condensation.

A water by-pass is included in the cooling system,

utilizing a hole in the front of, the cylinder block. This

allows a limited circulation of coolant, bypassing the

thermostat until thermostat opening temperatures are

reached. This system provides a uniform coolant tem-

perature throughout the engine, eliminating localized

hot-spots, improving exhaust valve life, provides fast

warmrup of lubricating oil and fast temperature rise in

the coolant which provides fast heater operation in cold

weather.

A thermostatic heat control on the exhaust manifold

during the warming up period, automatically directs the

hot exhaust gases against the center of the intake mani-

fold, greatly aids in proper vaporization of the fuel.

An automatic choke reduces the danger of raw or

unvaporized fuel entering the combustion chamber and

leaking into the oil reservoir.

An.
efficient crankcase ventilating system drives off

fuel vapors and aids in the evaporation of the raw fuel

and water which may find its way into the oil pan.

CRANKCASE BREATHER CAP

Clean and re-oil at every oil change..

CHEVROLET CHASSIS SERVICE MANUAL

LUBRICATION 0-15

CRANKCASE VENTILATION VALVE

VALVE TYPE

NOTE: Under prolonged dusty driving condi-

tions,
it is recommended that these operations

be performed more often. Every 12,000 miles

or 12 months the valve should be replaced.

Connecting hoses, fittings, flame arrestor and

crankcase breather cap (where used) should be

cleaned. At every oil change the system should

be tested for proper function and serviced, if

necessary.

FUEL FILTER

Replace filter element located in carburetor inlet if

flooding occurs, if engine surges during constant speed

operation (pulsating effect) or if poor performance is

experienced during acceleration or at higher speeds.

AIR CLEANER

NOTE: Under prolonged dusty driving condi-

tions,
it is recommended that these operations

be performed more often.

POLYURETHANE TYPE-

Every 12,000 miles clean element in solvent, squeeze

out solvent, then soak in engine oil and squeeze out

excess.

OIL WETTED PAPER ELEMENT TYPE-

First 12,000 miles inspect or test element; if satis-

factory, re-use element but recheck every 6,000 miles

until replaced. Element must not be washed, oiled,

tapped or cleaned with an air hose.

BATTERY TERMINAL WASHERS

Battery terminals have felt washers between top of

case and cable connections to minimize corrosive action

of battery acid. These felt washers should be saturated

with engine oil every 6,000 miles.

DISTRIBUTOR

4 and 6-Cylinder Engine—Remove distributor cap and

rotate lubricator 1/2 turn at 12,000 mile intervals. Re-

place at 24,000 mile intervals.

8-Cylinder Engine—Change cam lubricator end for end

at 12,000 mile intervals. Replace at 24,000 mile

intervals.

REAR AXLE AND 3-SPEED AND

OVERDRIVE, 4-SPEED TRANSMISSIONS

The passenger car operates under the most severe

lubrication conditions at high speed and requires a hypoid

lubricant which will meet this condition.

Recommended Lubricants

Standard Rear Axles—SAE 90 "Multi-Purpose" gear

lubricant.

Positraction Rear Axles—Use special Positraction

lubricant.
CAUTION: Straight Mineral Oil gear lubricants

must not be used in hypoid rear axles.

Transmissions—SAE 90 "Multi-Purpose" gear

lubricant.

The SAE 90 viscosity grade is recommended for year

round use. However, when extremely low temperatures

are encountered for protracted periods during the winter

months, the SAE 80 viscosity grade may be used.

"Multi-Purpose" Gear Lubricants

Gear lubricants that will satisfactorily lubricate hypoid

rear axles have been developed and are commonly re-

ferred to as ' 'Multi-Purpose" gear lubricants meeting

U.S.
Army Ord. Spec. MIL-L-2105B.

These lubricants can also be satisfactorily used in

manual transmissions.

CAUTION: With Positraction rear axles use

special Positraction lubricant.

"Multi-Purpose" gear lubricants must be manufac-

tured under carefully controlled conditions and the

lubricant manufacturer must be responsible for the

satisfactory performance of his product. His reputation

is the best indication of quality.

Lubricant Additions

The lubricant level in the axle and transmission hous-

ings should be checked periodically. (Every 6,000 miles.)

It is recommended that any additions required to bring

up the lubricant level be made using the same type lubri-

cant already in the housing.

When checking lubricant level in transmission or rear

axle the unit being cheeked should be at operating

temperature. With unit at operating temperature the

lubricant should be level with bottom of the filler plug

hole.
If the lubricant level is checked with the unit cold

the lubricant level should be 1/2 inch below the filler

plug hole.

Lubricant Changes

The rear axle lubricant does not require changing for

the life of the vehicle. If additions are needed, or when

refilling the axle after service procedures, use lubricants

described above.

POWERGLIDE TRANSMISSION

NOTE: Every 12,000 miles, it is recommended

that the Powerglide low band be adjusted as

specified in Section 7 of this manual.

Every 6,000 miles--Check fluid level on dipstick with

engine idling, selector lever in neutral position, parking

brake set and transmission at operating temperature. If

fluid level is below full mark on dip stick, adding a small

amount of Automatic Transmission Fluid, General Motors

Automatic Transmission Fluid (Part Numbers 1050568-

69,
70) is recommended. If this fluid is not obtainable,

use Automatic Transmission Fluid Type 'A' bearing the

mark AQ-ATF followed by a number and the suffix letter

'A'.
Recheck fluid level on dip stick and again add a

small amount of fluid if needed to bring level to full

mark. DO NOT OVERFILL.

CHEVROLET CHASSIS SERVICE MANUAL

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-28

providing a protective film to reduce the possibility

of infection.

3.
As soon as possible, call or consult an eye specialist

for immediate and future treatment.

REMEMBER -

pound of cure."
"An ounce of prevention is worth a

PRECAUTIONS IN HANDLING REFRIGERANT LINES

• All metal tubing lines should be free of kinks, be-

cause of the restriction that kinks will offer to the

flow of refrigerant. The refrigeration capacity of the

entire system can be greatly reduced by a single

kink.

• The flexible hose lines should never be bent to a

radius of less than 10 times the diameter of the hose.

• The flexible hose lines should never be allowed to

come within a distance of 2-1/2" of the exhaust

manifold.

• Flexible hose lines should be inspected at least once

a year for leaks or brittleness. If found brittle or

leaking they should be replaced with new lines.

• Use only sealed lines from parts stock.

• When disconnecting any fitting in the refrigeration

system, the system must first be discharged of all

refrigerant. However, proceed very cautiously re-

gardless of gauge readings. Open very slowly, keep-

ing face and hands away so that no injury can occur

if there happens to be liquid refrigerant in the line.

If pressure is noticed when fitting is loosened, allow

it to bleed off very slowly.

CAUTION: Always wear safety goggles when

opening refrigerant lines.

• In the event any line is opened to atmosphere, it

should be immediately capped to prevent entrance

of moisture and dirt.

• The use of the proper wrenches when making con-

nections on "O" ring fittings is important. The use

of improper wrenches may damage the connection.

The opposing fitting should always be backed up with

a wrench to prevent distortion of connecting lines or

components. When connecting the flexible hose con-

nections it is important that the swagged fitting and

the flare nut, as well as the coupling to which it is

attached, be held at the same time using three dif-

ferent wrenches to prevent turning the fitting and

damaging the ground seat.

• "O" rings and seats must be in perfect condition.

The slightest burr or piece of dirt may cause a leak.

• Sealing beads on hose clamp connections must be

free of nicks and scratches to assure a perfect seal.

MAINTAINING CHEMICAL STABILITY IN THE

REFRIGERATION SYSTEM

The metal internal parts of the Chevrolet refrigeration

system and the refrigerant and oil contained in the sys-

tem are designed to remain in a state of chemical

stability as long as pure R-12 and uncontaminated re-

frigeration oil is used in the system.

However, when abnormal amounts of foreign materials,

such as dirt, air or moisture are allowed to enter the

system, the chemical stability may be upset. When ac-

celerated by heat, these contaminates may form acids
Fig.
40-^-System Contaminants

and sludge and eventually cause the breakdown of com-

ponents within, the system. In addition, contaminates may

affect the temperature-pressure relationship of R-12,

resulting in improper operating temperature and pres-

sures and decreased efficiency of the system.

The following general practices should be observed to

insure chemical stability in the system.

• Whenever it becomes necessary to disconnect a

refrigerant or gauge line, it should be immediately

capped. Capping the tubing will also prevent dirt and

foreign matter from entering.

• Tools should be kept clean and dry. This also in-

cludes the gauge set and replacement parts.

• When adding oil, the container should be exception-

ally clean and dry due to the fact that the refrigera-

tion oil in the container is as moisture-free as it is

possible to make it. Therefore, it will quickly absorb

any moisture with which it comes in contact. For

. this same reason the oil container should not be

opened until ready for use and then it should be

capped immediately after use.

• When it is necessary to open a system, have every-

thing you will need ready and handy so that as little

Fig.
41—Gauge Set

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-37

VACUUM SYSTEM COMPONENT FUNCTION

Component

Air Door Diaphragm

Power Servo

Vacuum Relay Valve

Mode Door Diaphragm

Defroster Diaphragm

Transducer

Thermo Vacuum Valve
Vacuum Applied

Air Door Open to Outside Air

(Closed to Car Body)

Maximum Heat

Vacuum Applied to One Port Opens a Passage

Through the Valve to Allow Transducer Vacuum

to be Supplied to the Power Servo

Vacuum to Linkage Side

Air Flow Out Heater

Ducts

Full Airflow Out Heater

Outlet
Vacuum to Covered Side

Airflow Out of Upper

Outlets

Full Airflow Out Defroster

Outlets (Full De-ice)
No Vacuum Applied

Air Door Open to

Re circulated Air

(Open to Car Body)

Maximum Cooling

No Vacuum Applied Closes

Vacuum Supply to Power

Servo

Airflow Out of Upper and

Lower Outlets Door Open

1"
from 100% Lower Out-

let Position

Airflow Divided 1/3 Out

Defroster Outlets 2/3

Out Heater Outlets

Supplies Modulated Vacuum to Power Servo

Zero Voltage Applied to Transducer

Results in Maximum Vacuum Supply
10 Volts Applied to Transducer

Results in No Vacuum Supply

(Coolant Hot) Passes Vacuum When System is Calling For Outside Air

MAINTENANCE AND ADJUSTMENTS

EVAPORATOR CONTROL VALVE (POA)

(Chevrolet, Chevelle, Comoro, and Corvette

Four Season) (Chevrolet Comfortron)

The only check for proper POA valve operation is to

check the suction pressure at the valve as during a

performance test. The POA valve is an absolute valve

and will provide different gauge readings based on the

altitude where the readings are being taken. Correct

gauge reading at sea level is 29.5 psig. Gauge readings

will be one-half psi higher for each additional 1000 feet

of elevation. The following table lists gauge readings at

different altitudes. If a valve gives improper gauge

readings, it must be replaced since it is not repairable

or adjustable.

29.5

30.0

30.5

31.0

31.5

32.0

32.5

33.0

33.5

34.0

34.5
psig.

psig.

psig.

psig.

psig.

psig.

psig.

psig.

psig.

psig.

psig.
— Sea 1

— 1000

— 2000

— 3000

— 4000

— 5000

— 6000

— 7000

— 8000

— 9000
Level

ft.

ft.

ft.

ft.

ft.

ft.

ft.

ft.

ft.

— 10000 ft.
THERMOSTATIC SWITCH

(Universal and Chevy II All-Weather System)

Thermostatic switches used in Universal and All-

Weather systems differ only in the capillary tube sensing

unit.

The Chevy n All-Weather System thermostatic switch

has an air sensing capillary which is coiled and attached

to the front of the evaporator core with plastic plugs.

This type of unit is controlled by the temperature of the

air leaving the evaporator.

Universal systems make use of a thermostatic switch

with a fin sensing capillary or a self-supporting air sens-

ing capillary. This capillary controls the switch by

sensing the temperature of the metal fins or the air

leaving the fins.

Checking for Proper Operation

1.
Install the gauge set and set up the vehicle as

described under Performance Test.

2.
Movement of the temperature control knob should

result in a definite change in suction pressure and

cycling of the compressor clutch.

• If compressor continues to operate regardless of

the knob adjustment, it indicates that the points

CHEVROLET CHASSIS SERVICE MANUAL