oil type CHEVROLET CAMARO 1967 1.G Chassis Workshop Manual

GENERAL INFORMATION 0-5

Fig.
10—Delcotron Unit

Serial Number
Fig.
11—3-4 Speed Transmission Unit

Number Located on Lower Left Side of

Case Adjacent to Rear of Cover

(Saginaw)
Fig.
12-3 Speed Borg-Warner

Transmission Unit Number Located on

Boss Right Rear Comer of Extension

Fig.
13 — 4-Speed Transmission Source

Data Code is Located on Left Side of

Case at Lower Rear of Cover Flange

(Muncie)
Fig.
14—Starter Serial Number and

Production Date Stamped on Outer

Case,
Toward Rear
Fig.
15—Powerglide Transmission Unit

Number located on Right Rear Vertical

Surface of Oil Pan

16—The Turbo Hydra-Matic Transmission Serial Number

is Located on the Light Blue Plate

Location on the Right Side of the Transmission

tumbler, single bitted type having four tumblers. To

protect owners, automobile lock manufacturers stamp

the lock numbers on the lock core, shaft, etc., where they

will not show until lock is removed.

In addition, when a lock cylinder requires replacement

the lock code number may be obtained either from the

key, if available, or from old lock cylinder which is being

replaced.
Fig.
17—Battery Code Number Located on Cell

Cover Segment, Top of Battery

TUMBLERS

5 4 3 2 1

jjwvvvvvjl

SPRING RETAINER

Fig.
18-Side Bar Lock

CHEVROLET CHASSIS SERVICE MANUAL

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

LUBRICATION 0-17

LUBRICATE EVERY 6,000 MILES

LUBRICATE EVERY 12,000 MILES

LUBRICATE EVERY 36,000 MILES

Refill Positraction Rear Axle with

Special Lubricant Only.
GL—Multi-purpose
or
Universal Gear Lubricant4

WB-Wheel Bearing Lubricant

(Whenever Brakes are serviced)

CL—Chassis Lubricant

EO-EngineOil
AT-Automatic Transmission Fluid {Type
A)

BF-Brake Fluid

Fig.
32—Lubrication Diagram—Chevrolet

1.
Front Suspension

2.
Steering Linkage

3. Steering Gear
4.
Air Cleaner

5. Crankcase Breather Cap

6. Front Wheel Bearings
7. Transmission

8. Rear Axle

9. Oil Filter
10.
Battery

11.
Parking Brake

12.
Brake Master Cylinder

CHEVROLET CHASSIS SERVICE MANUAL

LUBRICATION 0-18

12

LUBRICATE EVERY 6000 MILES GL -Multi-purpose Gear Lubricant*

WB—Wheel Bearing Lubricant

LUBRICATE EVERY 12000 MILES (Whenever Brakes are serviced)

CL —Chassis Lubricant

LUBRICATE EVERY 36000 MILES E°-En9ine°il

"Refill Positraction Rear Axle with Special Positraction Rear Axle

Lubricant Only.
AT —Automatic Transmission Fluid (Type A)

SL —Steering Gear Lubricant

BF -Hydraulic Brake Fluid

1.
Front Suspension

2.
Steering Linkage

3. Steering Gear
Fig.
33—Lubrication Diagram—Chevelle

4.
Air Cleaner

5. Crankcase Breather Cap

6. Front Wheel Bearings
7. Transmission

8. Rear Axle

9. Oil Filter
10.
Battery

11.
Parking Brake

12.
Brake Master CylincU

CHEVROLET CHASSIS SERVICE MANUAL

LUBRICATION
0-19

.
3-SPEED
4-SPEED

7 OVER DRIVE

10 9 5 1 6 2 '
AUTOMATIC

3 12 11

LUBRICATE EVERY 6,000 MILES GL-Gear Lubricant*

WB-Wheel Bearing Lubricant

(Wh Bk
AT-Automdtic Transmission Fluid

^ WB-Wheel Bearing Lubricant (Type A)

-TV
LUBRICATE
EVERY 12,000 MILES (Whenever Brakes are serviced)

' CL—Chassis Lubricant

• LUBRICATE EVERY 36,000 MILES EO_Engine Oil
BF
-Brake Fluid

•Refill Positt

Special Lubricant Only.
Axl«
with

1.
Front Suspension

2.
Steering Linkage

3. Steering Gear
Fig.
34—Lubrication Diagram—Chevy I!

4. Air Cleaner

5. Crankcase Breather. Cap

6. Front Wheel Bearings
7. Transmission

8. Rear Axle

9.
Oil Filter
10.
Battery

11.
Parking Brake

12.
Brake Master Cylinder

CHEVROLET CHASSIS SERVICE MANUAL

LUBRICATION 0-20

3-SPEED

4—SPEED

AUTOMATIC

LUBRICATE EVERY 6000 MILES

LUBRICATE EVERY 12000 MILES

LUBRICATE EVERY 36000 MILES

*
Refill
positraction rear axle with

special lubricant only.
GL -GEAR LUBRICANT*

WB-WHEEL BEARING LUBRICANT

(WHENEVER BRAKES
ARE
SERVICED)

CL -CHASSIS LUBRICANT

CO-ENGINE
Oil;
AT -AUTOMATIC TRANSMISSION

FLUID (TYPE
A)

BF -BRAKE FLUID

Fig.
35—Lubricafion Diagram—Camaro

1.
Front Suspension

2.
Steering Linkage

3. Steering Gear
4.
Air Cleaner

5. Crankcase Breathe Cap

6. Front Wheel Bearings
7. Transmission

8. Rear Axle

9. Oil Filter
10.
Battery,

11.
Parking Brake

12.
Brake Master Cylinder

BODY LUBRICATION

See Body Service Manual
for
Body Lubrication,

cept Corvette)
(Ex-

CHEVROLET CHASSIS SERVICE MANUAL

LUBRICATION
0-21

6

3-SPEED

4-SPEED

AUTOMATIC

10

LUBRICATE EVERY 6,000 MILES GL -Multi-purpose
or
Universal Gear Lubrincant*

-(V LUBRICATE EVERY 12,000 MILES WB-Wheel Bearing Lubricant

V/^ (Whenever Brakes
are
serviced)
AT —Automatic Transmission Fluid (Type)

BF -Brake Fluid

a
LUBRICATE EVERY 36,000 MILES

* Refill Positraction Rear Axle with

Special Lubricant Only.
CL -Chassis Lubricant

EO—Engine
Oil

Fig.
36—Lubrication Diagram—Corvette

1.
Front Suspension

2.
Steering Linkage

3. Steering Gear
4.
Air
Cleaner

5. Front Wheel

Bearings
6. Transmission

7. Rear Axle

8.
Oil
Filter
9. Battery

10.
Parking Brake

11.
Brake Master Cylinder

BODY LUBRICATION POINTS (CORVETTE)

Lubricate the following items when possible.

Hood Latch Mechanism and Hinges --Apply light engine oil

to pivot points. Don't oil lock pins or catch plates.

i

Rear Compartment Lid Release and Hinges --Apply light

engine
oil.

Side Door Hinge Pins—Apply light engine oil.
Door Lock Rotor and Striker Plate—Apply light engine oil or

stainless stick lubricant.

Lock Cylinders—Lubricate with powdered graphite.

Window Regulators and Controls and Door Lock Remote

Link —Apply light engine
oil.

Gas Tank Filler Cap Hinge—Apply light engine oil.

Weatherstrips and Rubber Bumpers —Coat lightly with
a

rubber lubricant.

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