engine coolant CHEVROLET CAMARO 1967 1.G Chassis Workshop Manual
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Page 16 of 659
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
Page 42 of 659
HEATER AND AIR CONDITIONING 1A-19
Transducer
The transducer will produce a vacuum output that is
completely adjustable by varying the input voltage which
is provided by the amplifier. An increase in the applied
voltage results in a reduced vacuum output.
Power Servo
The power servo receives a vacuum signal from the
transducer, and it is capable of assuming any position
that is called for by the sensors, amplifier, and trans-
ducer. The power servo performs the following functions:
1.
Positions the temperature mix door via the tern-
perature door link. The position of this door~"de-
termihes the portions of hot and cold air being
blended and discharged into the car.
2.
Operates the power servo vacuum valve which de-
termines the air flow paths for heating and air
conditioning.
3.
Contains a printed circuit board which controls the
blower speed. The power servo position determines
the blower speed, but the control lever switch can
override the blower program depending upon the
customer's preference.
4.
Contains the "Hi" blower delay thermistor and the
"master delay thermistor".
Outside Air Diaphragm
When there is no vacuum applied to the hose, the out-
side air door is closed under spring tension. With the
door closed, air is taken from the inside of the auto-
mobile and re-circulated. Applying vacuum to the dia-
phragm opens the door for outside air.
Mode Door Diaphragm
Located behind the duct work, the mode door diaphragm
directs the air flow out either the air conditioning outlets,
the heater floor outlet, or both the heater and air con-
ditioning outlets. This is a push-pull type diaphragm
actuated by vacuum through two hoses and controlled by
the power servo vacuum switch.
Defroster Door
The defroster door is in the defog position until vacuum
is applied to the actuator to obtain either full heat or full
de-ice position.
High Blower Delay Thermistor
The high blower delay thermistor is located on the
power servo housing under the power servo vacuum valve
and printed circuit board assemblies. The function of the
thermistor is to operate the blower at a reduced speed
when the control is in the HI FRONT position until the
residual cold air is discharged from the duct work. This
function occurs when the blower first comes "on" in cold
weather.
Vacuum Tank
During heavy acceleration, the vacuum supply from
the carburetor drops. The vacuum tank, using a^ check
valve, stores vacuum so that under these conditions
vacuum will be available for the Comfortron.
Thermal Vacuum Valve (Hot Water Vacuum Switch)
When engine coolant temperature reaches 75°F, the
valve opens and supplies vacuum to the outside air door
if the system is calling for outside air.
Master Delay Thermister
This thermistor delays the initial operation of the
blower when the system is in the heat mode. In cold
weather this allows outside ram air to flow through the
system thereby purging the cold air in the ducts gradually
until the coolant reaches about 105°F. Then, the termis-
tor passes enough current to energize the master delay
relay which powers the blower at about nine volts.
Vacuum Relay Valve
This relay valve will shut off transducer vacuum to the
power servo whenever the vacuum from the engine intake
manifold falls below the vacuum in the power servo
supply line (engine stopped or operating at low manifold
vacuum). This causes the power servo to be held in
position when the vacuum supply falls too low to maintain
servo control.
Vacuum Bleeder
A vacuum bleeder insures that the outside air door will
close (diaphragm will bleed down) after the system has
been shut down. This prevents outside air from entering
when starting the system on a cold day before the engine
coolant temperature reaches 75°F.
Sun—Ambient Sensor
The sun-ambient sensor measures the temperature of
the air entering the air intake grille in front of the wind-
shield. The sensor is exposed to sun light so that it can
lower the in-car temperature slightly when the sun
is shining.
Ambient Switch
The ambient switch operates the air conditioning com-
pressor clutch. When the outside temperature is above
40° F. the switch will be closed and the compressor will
be running. This switch is included as| part of the sun-
ambient sensor assembly, but operates independently.
Resistor Assembly
The blower resistors are located in the evaporator
housing. The printed circuit board switch in the power
servo determines which of the resistors is being used,
and as in conventional systems, the resistors control the
blower speed.
System Operation
When starting the Comfortron System in cold weather,
the following sequence of events occurs:
1.
Initially the system is inoperative. In LO FRONT
position the master delay thermistor is warming
(self-heating because current is flowing through it)
CHEVROLET CHASSIS SERVICE MANUAL
Page 43 of 659
HEATER AND AIR CONDITIONING 1A-20
and its resistance is decreasing. In the HI FRONT
position, two thermistors (the master delay and high
blower delay thermistors) are warming. The air
door is in recirculation position until the engine
coolant reaches 75 degrees.
2.
The coolant reaches then 75 degrees and the thermal
vacuum valve opens applying vacuum to the air door
to admit outside air (unless the temperature dial is
set for cooling). Ram air will flow through the sys-
tem when the car is moving.
3.
Next, the master delay thermistor attains the tem-
perature at which it will pass sufficient current to
close the circuit through the master delay relay.
The relay circuit powers the blower motor at 9 volts.
4.
If the control is in the HI FRONT position, the high
blower delay thermistor will close the circuit
through the high blower relay which supplies full
available voltage to the blower motor. This function
occurs after the master delay thermistor has taken
effect because the high blower delay thermistor
uses the master delay type thermistor with a 10 ohm
1/4 watt resistor connected in
.
series. The nigh
blower delay thermistor must then warm to a higher
temperature than the master delay thermistor before
its resistance (plus that of the 10 ohm resistor)
drops enough to actuate the high blower relay.
5. If the controls are set for DE ICE, full outside air
and full voltage to the blower motor are effective
immediately regardless of temperatures or elapsed
times o
In accomplishing automatic control, the system follows
three steps to transform an electronic signal into me-
chanical energy through which the control is achieved.
Electronic Circuit
Two temperature sensors (Thermistors), and the duct
potentiometer connected in series, are located so as to
sense the temperature of the outside air, inside air and
system output air. The resistance of each sensor will
vary according to its temperature. The control head
temperature dial varies in resistance as it is adjusted by
the operator to suit his comfort requirements. The
resistance of the temperature dial control is applied
directly to the amplifier and is not in series with the
sensors and duct potentiometer. Thus temperature dif-
ferences in the sensor string plus the requirements fed
into the system by the operator cause changes in total
circuit resistance which allow a varying voltage flow
through the circuit.
Changing the Electronic Signal to Electrical Voltage
This minute voltage flow from the sensor string -
temperature dial circuit - is fed into the amplifier where
it is transformed into a usable amplifier output voltage,
the strength of which is determined by the strength of the
original amplifier input signal. This voltage is then
supplied to the transducer.
Changing the Electrical Voltage to a Vacuum Signal
Amplifier output voltage, varying according to tem-
perature requirements, is converted by the Transducer
into a modulator transducer output vacuum. This modu-
lated vacuum is applied to the Power Servo.
Changing the Vacuum Signal to Mechanical Energy
The Power Servo, controlled by the modulated Trans-
ducer output vacuum, operates the vacuum electrical and
mechanical components of the system as required to
provide automatic control of system operation.
Other major system components are mounted con-
ventionally in the engine compartment. Underhood com-
ponents and system airflow remain much the same as in
the Four-Season system except for the addition of the
automatic control provisions. The system operates on
100%
outside air, a mixture of outside and inside air, or
100%
recirculated air depending on the demands of the
system. The diaphragm operated .air selector door will
modulate outside air to the system during maximum air
conditioning requirements when the control unit is in
"Hi Front" position. Control of the blower is also com-
pletely automatic and dependent upon system demands.
Controls
The Comfortron controls the Chevrolet air conditioner
and heater in such a precise manner that the automobile
temperature remains relatively constant under all driving
conditions. By adjusting the thumb wheel on the Control
Head to any temperature desired between 65° and 85° F.
(See Figure 27) the automatic system will adjust the in-
car temperature even though the outside weather condi-
tions may vary considerably. The system will provide
maximum capacity for heating or cooling until the in-car
temperature reaches the pre-set Control Head Tempera-
ture. Where cooling is required, the system will start
immediately upon being turned "ON". During marginal
ambient temperatures the system will not always start
at the highest blower speeds of the control setting.
Therefore, occasionally the system can't be heard
starting*
Five over-riding functions are available so that special
conditions can be handled. Each Control Head function
will be discussed in detail below:
"Off" Position
In the "Off" position, the blower is turned off and the
outside air door is closed. No outside air should enter
the automobile.
"Lo Front" Position
The blower has five low to moderate speeds; Hi, M3,
M2,
M1 and Lo. The blower voltage will shift as directed
by the automatic controls. The "Lo Front" position
provides a quieter mode of automatic operation due to
reduction of blower noise.
"Hi Front" Position
The "Hi Front" position provides five high blower
speeds as called for by the automatic controls: The use
of the "Hi" blower speed results in a rapid cool down in
hot weather and rapid heating during cold weather. As
the in-car temperature approaches the temperature set-
ting on the Comfortron Control Head, the blower speed
will change, provided mild outside temperatures are
experienced. During very hot or cold weather, the blower
will reduce its speed only to the point where it is still
capable of maintaining the correct inrcar temperature.
"Rear" Position
The "Rear" position provides five high blower speeds.
The automatic controls select these speeds and blend the
discharge air to the proper temperature. By the use of
high blower speeds, increased airflow is obtained for
better rear seat passenger comfort.
CHEVROLET CHASSIS SERVICE MANUAL
Page 44 of 659
HEATER AND AIR CONDITIONING 1A-21
"De-Fog"
Position
In the event that the front windshield should require
removal of a fogging condition, the owner at his option
may direct air to the windshield. The "De-Fog" position
directs part of the air to the windshield while retaining a
certain amount through the floor outlets. The temper-
ature of the air remains the same as it was prior to the
control being placed in the "De-Fog" position. Five
blower speeds are available. The temperature of the air
and the blower speed are selected by the automatic
controls and are dependent upon the in-car temperature.
"De-Ice" Position
The "De-Ice" position provides full heat with "Hi"
blower directing the entire airflow to the windshield to
melt ice. The automatic controls are completely defeated
and as a result, full heat with "Hi" blower are the only
conditions that can be received. The system will turn on
immediately in this position even though the engine
coolant might be cold.
General Information
Three start up conditions can be achieved with
Comfortron.
Weather
Cold
Method of Starting System
System starts as soon as engine coolant is
hot.
Hot System starts immediately when AC is
required.
Any System starts immediately in "De-Ice"
position.
UNIVERSAL SYSTEM
A self-contained unit, the dealer installed Universal
System operates on recirculated air only and entirely
independent of the vehicle heater. Recirculated inside air
is drawn into the unit, passed through the evaporator core
and into the car through the adjustable outlets in the
evaporator case. The entire unit mounts compactly
beneath the dash. Temperature control is by means of a
thermostatic switch.
The compressor used with the Universal System is
identical to that used for the Four-Season system except
for displacement. Underhood components are similar in
placement to the Four-Season system.
Controls
Universal system controls are the AIR knob controlling
the three speed blower motor switch and the TEMP knob
which controls the setting of the thermostatic switchi
Switch adjustment is covered elsewhere in this section.
When operating this system the Heater must be fully off.
CHEVY II ALL-WEATHER SYSTEM
The Chevy n All-Weather Air Conditioning System,
Figure 33, operates in conjunction with the heater to
provide a complete air conditioning system operating on
either outside air, recirculated air or a combination of
both. The cooling unit attaches to the heater distributor
and utilizes the heater blower. Several controls allow
full use of either the heating or cooling features of the
system. During marginal weather, it is possible to pro-
vide heated air at floor level and cooled air at breath
level.
A schematic view of the air conditioning underdash
components is provided in Figure 34 to aid in under-
standing airflow and control operation.
The evaporator assembly, located in the passenger
compartment attached directly to the heater distributor,
contains the evaporator core, expansion valve, thermo-
static switch and the air conditioning "ON" knob. The
thermostatic switch, utilized as the cooling control, feels
the temperature of the cooled air leaving the evaporator
core and turns the compressor on and off in accordance
with cooling needs. Refrigerant lines connect the evap-
orator assembly to the other system components located
in the engine compartment.
The six cylinder air conditioning compressor, com-
pletely field serviceable, is bracket-mounted to the
engine and is belt driven from the crankshaft pulley. A
muffler assembly, designed to eliminate compressor
pulsations is an integral part of the compressor con-
nector block. The condenser is mounted on the radiator
support just ahead of the engine radiator. The receiver-
dehydrator, with its sight glass, is located on the right
fender skirt.
Controls
Control of the air conditioning system is achieved
through the use of the heater control on the instrument
panel as well as the two knobs located on the air condi-
tioning unit itself (fig. 35).
Air Conditioning "ON" Knob
Labeled "Pull for Air Cond.", this knob diverts air-
flow from the floor distributor and through the air condi-
tioning unit. Initial movement of this knob also actuates a
switch, located at the damper door, which energizes the
compressor clutch thus putting the system into operation
and under the control of the thermostatic switch.
Temp-Cool Knob
This knob controls the thermostatic switch. Turn the
knob clockwise for more cooling, counter-clockwise for
less cooling.
Air Lever
This lever actuates the damper within the assembly
which chooses between recirculated air or outside air.
Fig.
31-Universal Air Conditioning Unit
CHEVROLET CHASSIS SERVICE MANUAL
Page 47 of 659
HEATER AND AIR. CONDITIONING 1A-24
Fig. 35-Controls-AII Weather (Chevy II)
The heater components of the system are similar to
the standard Corvette heater with hoses routing engine
coolant to and from the heater core. A vacuum operated
shutoff valve assures that no coolant will pass through
the heater core until the system calls for heat.
Four control knobs surrounding the clock on the in-
strument panel center console provide full control of the
heating and cooling functions of the air conditioning
system.
The general arrangement of the system components
is pictured in Figure 37 while a schematic view of the
system will be found in Figure 36.
Controls Corvette
Four control knobs, grouped around the clock on the
instrument panel central console, provide full control
of the heating and cooling functions of the Corvette Air
Conditioning System. Each of the knobs, through a bowden
cable, operates one of the air diverter doors in the air
distributor assembly. In addition, the AIR COND.-PULL
knob operates the compressor switch; blower speeds are
controlled by turning the AIR PULL knob; and the heater
hot water valve vacuum switch is actuated by the COOL
IN-HQT PULL knob.
Air Conditioning "ON" Knob
The "AIR COND. PULL" knob controls the positioning
of the air diverter door which routes conditioned air
through either the dash diffuser ducts or the floor dis-
tributor outlets. Movement of this knob (hence, movement
of the selector door) also controls' the compressor
switch. When the door is positioned to send air through
the dash outlets the compressor is automatically turned
on to place the cooling system in operation and the fan
is turned on to LOW speed.
Blower Switch and Air Selector
The AIR PULL-FAN knob operates the selector door
in the right hand plenum chamber and may be set to allow
full outside air, full inside air, or a mixture of the two to
DEFROSTER DOOR
OPERATED BY
DEFROSTER KNOB
AIR CONDITIONING DOOR
OPERATED BY
AIR COND. PULL KNOB
BLOWER
OPERATED
BY TURNING
AIR KNOB
AIR DOOR
OPERATED
BY PULLING
AIR KNOB
OUTSIDE
AIR
CONTROLS
HEAT DOOR
OPERATED BY
COOL IN-HOT PULL
KNOB
L.H. OUTLET
CENTER
OUTLET
R.H. OUTLET
AIR COND.
PULL
COOL IN
HOT PULL
AIR PULL
LO-MED-HI
DEFROSTER
PULL
Fig.
36—Corvette Four-Season System Schematic
CHEVROLET CHASSIS SERVICE MANUAL
Page 48 of 659
HEATER AND AIR CONDITIONING 1A-25
Fig.
37—-Corvette Four-Season System Components
pass through the system. For heating operations it is
suggested that Ml outside air (knob Mly OUT) be used.
For cooling operations under extreme heat conditions
push knob fully in (recirculated inside air); under moder-
ate temperature conditions pull the knob out to the detent
position (a misxture of outside air and inside air); and
under mild temperature conditions the knob may be
pulled fully out (outside air).
After the AIR PULL knob is set to permit air to pass
through the system, the knob may be rotated to control
the three-speed blower. When the AIR COND.-PULL
knob is pulled out the low blower is in operation. Select
higher speeds as desired.
Temperature Adjustment
The COOL IN-HOT PULL knob controls the air output
temperature during both heating and cooling operations.
A vacuum switch (operated by the temperature door
actuating cam) controls a vacuum operated water valve
which allows engine coolant to flow through the heater
core only when this knob is pulled out.
During heating operation cold ambient air enters the
conditioner, passes through the inoperative cooling core
and then passes through and around the heating core
(the final mixture of hot and cold air being determined
by the control knob - temperature door setting) and then
enters the car.
Cooling operation is exactly the same except that the
cooling core (evaporator) will be in operation at Ml
capacity, removing as much heat and humidity as pos-
sible from the warm ambient air flowing through it.
The COOL IN-HOT PULL knob may then be pulled out
as needed to temper this maximum cold airflow should
it become necessary.
Defroster Control
This control acts to divert heated air from the floor
distributor duct into the defroster duct for windshield
defogging, defrosting and deicing operations. A detent
is built into the defroster linkage to indicate the setting
at which a small portion of the heater air will be con-
tinaully passed over the windshield, thus keeping it clear.
Operating Instructions
Remember that the air conditioning system may be
used for heating or cooling during any season of the
year to provide just the desired comfort conditions.
Cooling
1.
"Air Cond-Pull". This knob should be pulled fully
out.
2.
"Cool In-Hot Pull". This knob should be pushed
fully in for maTriTr»"Tn cooling. Pulling out the knob
as required will mix warm air with the cool air to
temper the cool air output.
3.
"Air Pull-Fan". Set this knob fully in during ex-
treme heat conditions; at the detent position during
moderate temperature conditions; fully out during
mild temperature conditions or whenever tempering
of the cooled air flow is necessary. Turn the knob
CHEVROLET CHASSIS SERVICE MANUAL
Page 56 of 659
HEATER AND AIR CONDITIONING 1A-33
within the system. The following fixed conditions must be
adhered to in order to make it possible to compare the
performance of the system being tested with the stan-
dards below:
1.
Doors and windows closed. (Car inside or in shade.)
2.
Hood up and engine exhaust suitably ventilated.
3.
Vehicle in NEUTRAL with engine running at 2000
rpm.
4.
Air Conditioning controls set for -
• Maximum cooling.
• High blower speed.
5.
TEMP knob and AIR knob set for full recirculating
air. On Comfortron systems* move the control lever
to REAR and pull the white vacuum hose from the
transducer. Plug the hose. An alternate method is to
install the J-22368 Tester (described later in this
section) and operate it on MANUAL control to main-
tain maximum cooling and blower speed.
6. Gauge set installed.
7.
System settled out (run-in approximately
10
minutes).
8. A thermometer placed in front of vehicle grille and
another in the right hand diffuser outlet.
PERFORMANCE DATA
The following Performance Data define normal opera-
tion of the system under the above conditions. Relative
humidity does not appear in the tables because after
running the prescribed length of time on recirculated air
and maximum cooling, the relative humidity of the air
passing over the evaporator core will remain at ap-
proximately 35% to 40% regardless of the ambient
temperature or humidity.
Should excessive head pressures be encountered at
higher ambient temperatures, an 18" fan placed in front
of the vehicle and blowing into the condenser will provide
the extra circulation of air needed to bring the pressures
to within the limits specified.
NOTE: Higher temperatures and pressures will
occur at higher ambient temperatures, fti areas
of high humidity it is possible to have ther-
mometer and gauge readings approach but not
reach the figures listed in the performance
tables and still have a satisfactory operating
unit. However, it is important to remember that
low pressure has a direct relationship to nozzle
outlet temperature. If pressure is too low, ice
will gradually form on the evaporator fins, re-
stricting airflow into the passenger area and
resulting in insufficient or no cooling.
Four-Season and Comfortron System
Chevrolet and Camaro
Chevelle
(Refrigerant
Charge
=
Temperature
of Air
Entering Condenser
Engine rpm
Compressor
Head Pressure
Evaporator Pressure
at POA
Discharge Air Temp,
at Right Hand Outlet
3
Lbs. -
70°
145-
155
38-
41
80°
170-
180
12 02
90°
.)
100°
2000
205-
215
29.5 -
39-
42
41-
43
255-
265
30.5
42-
45
110°
260-
270
psi
43-
46
120°
295-
305
45-
48
(Refrigerant Charge =
Temperature of
Air Entering
Condenser
Engine rpm
Compressor Head
Pressure
Evaporator
Pressure
at
POA
Discharge Air
Temp, at Right
Hand Outlet
3 Lbs. -
70°
150
160
37-
40
80°
175
185
12 Oz.)
90° 100°
2000
210 250
220 260
29.5 - 30.5
37-
40
38-
39-
41 42
110°
280
290
psi
40-
44
120°
290
300
41-
45
Corvette
(Refrigerant Charge =
Temp, of Air
Entering Condenser
Engine rpm
Compressor
Head Pressure
Evaporator
Pressure
at
POA
Outlet
Air
Temperature
(at Right
Outlet)
3
Lbs.
70°
150-
170
38-
40
- 4 Oz.)
80°
175-
195
29
38-
40
90°
2000
200-
200
100°
i*pm
240-
260
110°
285-
300
5-
30.5 psi
40-
42
41-
43
43-
45
120°
325-
335
45-
47
Alt Weather System
Chevy II
(Refrigerant
Charge
=
Grille Air
Temperature
Engine rpm
Compressor Head
Pressure
Compressor Suction
Pressure**
Discharge Air Temp,
at R/H Outlet**
2-1/2 Lbs.)
70°
120-
140
13
32-
37
80°
150-
160
14
CO
OO
CO
CO
90°
100°
1500
175-
185
15
35-
40
220-
230
15
36-
41
110°
240-
250
19
37-
42
120°
265-
275
19
38-
43
**When Compressor Clutch Releases
COMFORTRON SYSTEM OPERATIONAL TEST
This test, designed as a quick check of total system
operation, must be made with the engine operating at
minimum of 2000 rpm and coolant warm. Wait several
seconds between operations to allow the system to move
through its sequence of operation and arrive at the pre-
scribed mode of operation.
1.
With control lever in the OFF position, and Tem-
perature Dial at 65°F.
a. System is turned OFF, there is no air flow from
any of outlets.
2.
Control lever in HI Front and Temperature Dial set
at65°F.
CHEVROLET CHASSIS SERVICE MANUAL
Page 96 of 659
HEATER AND AIR CONDITIONING 1A-73
Fig.
105—Comfortron Control Head
10.
Introduce R-12 vapor at cylinder (room) temperature
and pressure.
11.
Leak test all fittings and connections and give partic-
ular attention to a leak test at the compressor shaft
seal if compressor has not been leak tested on the
bench.
12.
Complete system processing and charge system.
FUSES
A fuse, located in the junction block protects the entire
air conditioning system except for the blower when op-
erating at high speed.
A second fuse, to protect the high speed blower circuit,
is located in the electrical wiring between the horn relay
and the Air Conditioner relay (except Universal). The
Universal unit has a fuse in the line between the ignition
switch and the Air Conditioner blower switch. See the
specification page for the proper replacement fuse.
FOUR SEASON HEATER COMPONENTS
Corvette
The heater components of the system are, in general,
much the same as those of the standard Corvette heater.
Heater hoses carry the engine coolant to the heater core,
located in the air distributor duct beneath the instrument
panel.
A significant difference is that in the Corvette Air
Conditioning System there is no flow through the heater
core until the COOL IN-HOT PULL knob is pulled out.
This movement opens the vacuum switch on the air
distributor assembly and allows vacuum to be applied
to the water valve mounted in the engine compartment,
opening the valve. Thus the heater core is unheated
until needed, at which time it receives full flow of the
engine coolant. Air passing through the core receives
maximum heat which is tempered by mixing with un-
heated air before entering the passenger compartment.
Heater Core
Replacement
The heater core in the Corvette Air Conditioning
System is removed in the same manner as the core in
the Corvette heater. The distributor assembly must first
be removed from under the dash as covered previously
in this section before the core can be removed and
replaced.
Water Valve
Installation of the water valve is illustrated in Figure
113.
An inoperative valve must be replaced.
Chevrolet
Heater Core
Removal
1.
Disconnect battery ground cable.
2.
Drain radiator
3.
Remove right front fender and skirt assembly.
Fig.
106—Comfortron Temperature Dial Adjustment
Fig.
107—Amplifier Removal
CHEVROLET CHASSIS SERVICE MANUAL
Page 267 of 659
ENGINE 6-2
remotely at the starter, with a special jumper
cable or other means, the primary distributor
lead must be disconnected from the negative
post on the coil and the ignition switch must be
in the "ON" position. Failure to do this will
result in a damaged grounding circuit in the
ignition switch.
3.
Crank engine through at least four compression
strokes to obtain highest possible reading.
4.
Check and record compression of each cylinder.
5.
If one or more cylinders read low tor uneven, inject
about a tablespoon of engine oil on top of pistons
in low reading cylinders (through spark plug
port).
Crank engine several times and recheck
compression.
• If compression comes up but does not necessarily
reach normal, rings are worn.
• If compression does not improve, valves are
burnt, sticking or not seating properly.
• If two adjacent cylinders indicate low compres-
sion and injecting oil does not increase compres-
sion, the cause may be a head gasket leak between
the cylinders. Engine coolant and/or oil in cylin-
ders could result from this defect.
NOTE: If a weak cylinder cannot be located
with the compression check, see "Cylinder Bal-
ance Test" under "Additional Checks and Adjust-
ments" in this section.
Service and Install Spark Plugs (Fig. 2)
1.
Inspect each plug individually for badly worn elec-
trodes,
glazed, broken or blistered porcelains and
replace plugs where necessary. Refer to spark plug
diagnosis information presented in Section 6Y for an
analysis of plug conditions.
2.
Clean serviceable spark plugs thoroughly, using an
abrasive-type cleaner such as sand blast. File the
center electrode flat.
3.
Inspect each spark plug for make and heat range. All
plugs must be of the same make and number.
4.
Adjust spark plug gaps to specifications using a
round feeler gauge.
PORCELAIN
INSULATOR
INSULATOR CRACKS
OFTEN OCCUR HERE
CENTER ELECTRODE
[FILE FLAT WHEN
ADJUSTING GAP-
[DO NOT BEND!
(PROPER GAP)
(BEND TO ADJUST GAP)
CAUTION:
adjust gap.
Fig.
2 - Spark Plug Detail
Never bend the center electrode to
Always adjust by bending ground or
side electrode.
If available, test plugs with a spark plug tester.
Inspect spark plug hole threads and clean before in-
stalling plugs. Corrosion deposits can be removed
with a 14 mm. x 1.25 SAE spark plug tap (available
through local jobbers) or by using a small wire brush
in an electric drill. (Use grease on tap to catch
chips.)
ADJUST DWELL
ANGLE SETTING OR
POINT OPENING
Fig.
1 - Checking Compression
Fig.
3 - Distributor (In Line)
CHEVROLET CHASSIS SERVICE MANUAL
Page 271 of 659
ENGINE 6-6
CHOKE VALVE
COMPLETELY
CLOSED
PULL UPWARD ON
ROD TO END OF
TRAVEL
BEND ROD
TO ADJUST
ROD IN BOTTOM
OF SLOT
BOTTOM OF
ROD SHOULD
EVENWITH
TOP OF
HOLE
CHOKE VALVE
CLOSED
BOTTOM OF
ROD SHOULD
BE EVEN WITH
TOP OF HOLE
TOP OF ROD
SHOULD BE EVEN
WITH BOTTOM
OF HOLE (CHOKE
CLOSED)
^..BEND ROD TO
ADJUST
_PULL DOWNWARD
ON ROD TO CON-
TACT STOP
L6 (TYPICAL)
V8 327-275 HP
V8 350-295 HP
BEND ROI
TO ADJUST
PULL UPWARD ON
ROD TO CONTACT
STOP ON BRACKET
ALL V8 (EXCEPT 327-275 HP
AND 350-295 HP)
Fig.
11 - Remote Choke Adjustment
sequence outlined on Torque Sequence Chart. A slight
leak at the intake manifold destroys engine performance
and economy.
Service Fuel Lines and Fuel Filter
1.
Inspect fuel lines for kinks, bends or leaks and cor-
rect any defects found, • • •
2.
Inspect filter and replace if plugged.
NOTE:
If a complaint of poor high speed per-
formance exists on the vehicle, fuel pump tests
described in Section 6M should be performed.
Service Cooling System
1.
Inspect cooling system for leaks, weak hoses, loose
hose clamps and correct coolant level, and service
as required.
NOTE:
A cooling system pressure test, as de-
scribed in "Additional Checks and Adjustments"
in this section, may be performed to detect
internal or external leaks within the cooling
system.
Check and Adjust Accelerator Linkage
1.
Disconnect accelerator rod at carburetor throttle
lever.
2.
Hold carburetor throttle lever in wide position.
3.
Pull accelerator rod to wide open position. (On ve-
hicles equipped with automatic transmission, pull
through detent).
4.
Adjust accelerator rod to freely enter hole in carbu-
retor throttle lever.'
NOTE:
Accelerator linkage is outlined in de-
tail in Section 6M.
5. Connect accelerator rod at throttle lever.
Service Crankcase Ventilation (Fig. 10}
All engines have either "Positive" or "Closed Positive"
ventilation systems utilizing manifold vacuum to draw
fumes and contaminating vapors into the combustion
chamber where they are burned. Since it affects every
part of the engine, crankcase ventilation is an important
function and should be understood and serviced properly.
In both "Positive" and "Closed Positive" ventilation,
air is drawn through the engine, (through a regulating
valve) into the manifold, drawing' crankcase vapors and
fumes with it to be burned. "Positive" ventilation uses a
vented-meshed cap for clean air intake to the engine,
while . "Closed Positive" ventilation system draws the
clean air from the carburetor air cleaner and has a
nonvented oil filler cap.
1.
Ventilation valve may be checked as outlined under
"Additional Checks and Adjustments".
2.
Inspect for deteriorated or plugged hoses.
3.
Inspect all hose connections.
4.
On closed positive ventilation systems, remove flame
arrestor and wash in solvent then dry with com-
pressed air.
Service Air Injection Reactor System
Inspect air injection reactor system for evidence of
leaks,
deteriorated hoses, cracked air manifolds or tubes
and loose hose clamps. Inspect air injection pump belt
condition and tension. Make all necessary repairs as
outlined in "Section 6T".
Because of the relationship between "Engine Tune Up"
and "Unburned Exhaust Gases", the condition of Engine
CHEVROLET CHASSIS SERVICE MANUAL