1967 CHEVROLET CAMARO check engine

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

HEATER AND AIR CONDITIONING 1A-34

a. Blower comes on High speed.

b.
Cold air comes from A/C outlets.

3.
Rotate Temperature Dial to 85°F.

a. Blower speed will decrease to Low speed then

increase to Medium or High.

b.
Air temperature changes from Cold to Hot and

comes out heater outlet.

4.
Move control lever to LOW Front, with Temperature

Dial at 85°F. Blower operates at Low and Medium

speeds.

5.
Move control lever to Rear, set Temperature Dial

at 65°F.

a. Blower goes to High speed and maintains high

air flow.

b.
All air comes from A/C outlets.

6. Move control lever to DE-FOG.

a. Blower is on Medium or High Speeds.

b.
Air comes from Defroster and Heater Outlets.

7.
Move control lever to DE-ICE.

a. Blower is on High Speed.

b.
Air temperature goes to warm and most of air

comes from defroster nozzle, with small amount

of air coming from heater outlet.

c. Outside air door is open - (door valve is closed

to car body).

8. Move control lever to REAR (dial at 65°). Outside

air door moves outboard. (Door valve is open to

car body).

CHEVROLET COMFORTRON TESTER

The J-22368 Automatic Temperature Control Tester

when in AUTOMATIC position, may be used to perform
Comfortron system checks without disturbing normal car

operation.

Under MANUAL control tester allows the operator to

set and hold a predetermined blower speed
and.
temper-

ature. The tester can also be used to measure external

system voltages by using the probe.

To Install the Tester

1.
Remove the three-terminal male connector from the

Amplifier on the Comfortron control head.

2.
Plug this connector into the three terminal female

connector (with yellow wire)
on
the Tester.

3.
Plug the remaining three-terminal male connector

on the Tester into the Amplifier on the control head.

4.
Attach the black ground lead to any good ground

point available in the car.

5.
Remove the large vacuum hose from Transducer and

connect it to the Tester vacuum hose nipple.

6. Connect the Tester vacuum hose (short hose) to the

Transducer.

Quick Test Procedure

With the J-22368 Tester installed as outlined above,

the following quick checks may be made to pinpoint

the cause of system malfunctions. This quick check

procedure is reproduced on the "swing out" plastic

instruction card attached to the back of the Tester.

Before performing the checking procedure, start the

engine and allow to run on fast idle until operating

temperature is reached. Then set the dash control lever

to HI-FRONT position and the dash control Temperature

Dial to 75° and proceed with the following steps:

Step

1

2

3

4

5A

5B
Tester Settings

Rocker

Switch

Manual

Manual.

Manual

Manual

Manual

Auto-

matic
Voltage

Source

Sensor

Amplifier

or

Control

Cal.

Trans-

ducer

Amplifier

or

Control

Cal.

Amplifier

or

Control

Cal.
Manual

Control

150

150

a. Max.

Heat*

b.
Max.

Cold*

a. Max.

Cold*

b.
Max.

Heat*

Set to

150 for

Comfortron

System

Same as 5A.

Allow 5 min.

for system

to stabilize

with doors

and windows

closed.
Tester Should

Indicate:

Battery Voltage

Battery Voltage

0-4 Volts

8 Volts Min.

8 Volts Min.

0-3 in. Vac.

0-4 Volts

9 in. Min. Vac.

6.5 Volts

5.5 to 7.5 Volts
To Correct Abnormal Indication:

Check fuse and wiring.

Check for open in sensor circuit.

See Service Manual:

Malfunctioning Amplifier or Temperature

Dial.

Check for open or bad ground in trans-

ducer circuit or replace transducer.

Rotate car temperature dial until meter

reads 6.5 volts. Car temperature should

'•- indicate 75°. If not, see temperature

calibration which follows.

After 5 minutes of operation check for

defective sensor.

•This setting should result in HIGH blower speed. Refer to shop manual for further operational checks.

CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-35

Checking Condition of Thermistors (Sensors)

1.
Install Tester J-22368 as previously described.

2.
Start the engine and run at fast idle. Move the

Comfortron control lever to HI-FRONT.

•Set Rocker switch to MANUAL.

•Set Manual Control Knob to 150 ohms on scale.

3.
Set the Tester Voltage switch to AMPLIFIER.

4.
Rotate Comfortron Temperature dial until the Tester

voltmeter reads 6.5 volts. The dial should read 75°,

Adjust dial if necessary.

5.
After car has run (windows and doors closed) for at

least 10 minutes, switch Rocker switch to AUTO-

MATIC. Voltage reading should remain at 6.5. A

change in the voltage indicates a bad sensor.

6. If a bad sensor is indicated in Step 5, check each

sensor, disconnected from the system, with an ohm-

meter. Approximate resistance of each sensor at

75°F.
should be as follows:

In-car Sensor — 50-75 ohms

Ambient Sensor --,55 ohms or less

Duct Delay Sensor -.- 25-75 ohms

Feedback

Potentiometer —

Master Delay

Thermistor -- 70 ohms

High Blower Delay

Thermistor -- 80 ohms including

10 ohm resistor

(Located in Power Servo casting)
VACUUM
ELECTRICAL LEAD

GROUND

LEAD

Fig.
47—Comfortron System Tester x

COMPLETE SYSTEM CHECKS

The following information should be used whenever

preliminary checks indicate the need for further, more

specific, tests. Together with the Electrical Test Dia-

gram (fig. 49) and the Vacuum Diagram (fig. 50),

they may be used to accurately pinpoint any malfunction

of the system.

Fig.
48—Comfortron Tester Installation

CHEVROLET OU
SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-36

(These tests should be performed with the engine at operating temperature.)

SYSTEM CHECKS

Control

Head

Setting

High

Front

Lo

Front

Lo

Front

Hi

Front

Hi

Front
Tester Settings

Function

Manual

Manual

Manual

Manual

De-ice

65° on

Temp.

Dial

Hi

Front

Hi

Front

Hi

Front
Auto-

Matic

1 1

Auto-

matic

Manual

Manual
Manual

Control

Max.

Heat

Rotate

from

Max.

Heat to

Max.

Cold

150

Max.

Cold

Max.

Cold

Max.

Cold

Max.

Heat

Max.

Heat

Max.

Cold
Voltage

Trans-

ducer

Trans-

ducer

Ampli-

fier

Trans-

ducer

Probe

Probe

Trans-

ducer

Trans.
Tester Should

Indicate:

High Blower

Maximum Heat

Reduced Blower

Speed

Complete series of

blower changes from

Hi to Lo to Hi

again.

AMPLIFIE:

Remove conn, from c

Voltage reading she

Short this lead to grc

Voltage reading she

No voltage change in<

COMPRESSOR C

Cooling System

Operation

DE-ICE i

Assuming rest of

system is operating

normally: Max. Heat

1
to windshield.

SENSOR STR

•—

TRAtfSDtfC

0-3"
Vac. Reading

8 Volts Min.

9"
Min.
Vac.
Reading

0-4 Voltage Reading
If not, check

the following:

Fuse in Slock

In Line Fuse

High Blower

Delay Relay

Duct Delay

Thermistor

High Blower

Delay Sensor

Power Servo

Blower Switch

Resistor

Blower Motor

Wiring Harness

Blower Switch

Master Delay

Thermistor

Master Delay

Relay

Resistor

Power Servo

Blower Motor

CHECK

Resistor

I CHECK
Electrical Diagram

Probe Points:

1-2

8-9

10-21

20

18

19

*
9-46

-r

^2-3
15

16

Checked during

above procedure.

(This is a com-

plete step-by-step

high blower circuit

check which also

checks wiring

harness.)

4

5

6

L2-13

L4

""§2-15

39-46

1
16 1

14

22-40-42-44-15

.ontrol head temperature dial.

>uld be 9 volts minimum,

jund.

>uld be 0 volts,

iicates malfunctioning of amplifier.

JUTCJH CHUCK

Compressor Clutch

(Grille Temp, must

be above 40°.)

IRCUIT

Blower Switch

Master Delay

Relay

Transd

NGCl
ucer

Sensor String

2R CHECK

Transducer voltage

&t Max. Cold

position)

Transducer Ground

Hi Blower Outside

air (air door closed

to car body). Hot air

from heater outlets.

Hi Blower Recirc.

Air (air door open

to car body) cold air

from A/C outlets.
24-25-26-27-28
Voltmete

should re
ad

Battery Voltage

Battery Voltage

Battery Voltage

. Vtinimum
6
volts

Battery Voltage

Minimum
6
volts

Battery Vo]

Batterv Vo]
Ltage

Ltage

Battery Voltage

Batterv Voltage

3a

Bai
:terv Vo

tterv Vo
tage

tage

Minimum
6
volts

Batterv Voltage

Minimum
6
volts

Battery Voltage

Minimum
8
volts

Minimum 8 volts

Minimum 8 volts

Batterv Voltage

Minimum 8 volts

1 III • II »ll. —..• —•— . !!•• 1

Battery Voltage

3-23

20-10-21

38

29-30-31-32-33-

34-35-36

37-38

Defective Power Servo; Leak in Vacuum

System; Temp.; Door Link Disconnected

or Jammed; Defective Vacuum Relay

Valve

Defective Mode Door Diaphragm
Batterv Voltage

Battery Voltage

Zero Voltage

Battery Voltage

Battery Voltage

CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-40

THERAAAL VACUUM

VALVE
TO ENGINE

VACUUM

SOURCE

VACUUM STORAGE

TANK

OUTSIDE AIR

DIAPHRAGM

MODE

DIAPHRAGM

VACUUM

RELAY
BLACK

DEFOG-DEICE

DIAPHRAGM

GREEN

BLACKj ||
|
BROWN

CONTROL

VALVE

Fig.
50—Comfortron Vacuum Diagram

are fused which will lead to evaporator freeze-up.

Replace the switch.

• If the compressor does not operate regardless of

the position of the knob a loss of the power

element charge is indicated provided that it has

been established that power is supplied to the

switch. This, of course, results in no cooling.

Replace the switch.

• Check the screw threads for stripped or other-

wise damaged threads.

Adjusting Switch

H, after checks above, the switch seems to be operating

properly,

follows:
adjust for proper setting if necessary, as
1.
(Chevy II All-Weather) Turn the outer air deflector

in the face plate so that the attaching screws may

be removed; Then remove the control knobs, bezels

and the thermostatic switch. (Universal) remove the

face plate retaining screws. Pull the faceplate away

from the case when ready to turn the switch adjusting

screw.

2.
Vehicle must be set up as in Step 2 above.

3.
The suction side of the system, read on the low

pressure gauge, should pull down to the pressure

shown in the chart in Performance Test under the

ambient temperature at the time the switch is being

set.

4.
If the low side pulls down lower than the prescribed

pressure at the end of each cooling cycle, turn the

adjusting screw (See Figure 54) clockwise in single

CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-42

EXTERNAL

EQUALIZER LINE

Fig. 54—Thermosratic Switch Adjustment

POORLY LOCATED POWER ELEMENT BULB

Normal Pressure.

Poor Cooling.

ENGINE IDLE COMPENSATOR

This additional aid to prevent stalling during prolonged

hot weather periods is included with all air conditioned

vehicles. The idle compensator is a thermostatically

controlled air bleed which supplies additional air to the

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

conditioning systems, the compensator is located within

the carburetor and is accessible when the engine air

cleaner is removed. On all other vehicles the compen-

sator is threaded into a manifold, fitting below the

carburetor. All compensators are factory set and are

non-adjustable. A malfunctioning unit should be replaced.

NOTE:
If engine idle is erratic, hold the idle

compensator valve closed with a pencil or

wooden dowel while adjusting the idle mixture

screw(s). Never attempt to bend the bimetal

strip or attempt any valve adjustment.

EVACUATING AND CHARGING PROCEDURES

1967 AIR CONDITIONING SYSTEM CAPACITIES

Four-Season Systems (Chevrolet and Chevelle)

Universal System (Chevrolet, Chevelle and Camaro)

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

3 lbs., 12 oz.

3 lbs.

2 lbs., 8 oz.
Oil Charge

11 ozs. 525 viscosity

11 ozs. 525 viscosity

11 ozs. 525 viscosity

PURGING THE SYSTEM

In replacing any of the air conditioning components the

system must be completely purged or drained of re-

frigerant. The purpose is to lower the pressure inside

the system so that a component part can be safely

removed.

1.
With engine stopped install high and low pressure

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

sure gauge fittings (see "Installing Gauge Set to

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

manifold, open high pressure gauge valve and dis-

charge the vapor slowly through the center

connection.

CAUTION: Do

compressor

refrigerant.
not open valves too much or

oil may be discharged with the

A rag wrapped around the end of

the center gauge line will prevent the splashing

of oil in the event of accidental rapid discharge.

CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-43

LOW PRESSURE

CONTROL
HIGH PRESSURE

CONTROL

3

VACUUM

CONTROL
4

FREON

CONTROL

Fig,
56—Charging Station Controls

3.
When the pressure is reduced to below 100 pounds

on the high pressure gauge, open the low pressure

gauge valve and continue discharging until all re-

frigerant has been released. Close both gauge valves.

EVACUATING AND CHARGING THE SYSTEM

GENERAL NOTE: La all evacuating procedures

shown below, the specification of 26-28 inches

of Mercury vacuum is used. These figures are

only attainable at or near Sea Level Elevation.

For each 1000 feet above sea level where this

operation is being performed, the specifications

should be lowered by 1 inch. Example: at 5000

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

normally be obtained.

Whenever the air conditioning system is open for any

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

has been evacuated to remove air and moisture which

may have entered the system.

The following procedures are based on the use of the

J-8393 Charging Station.

Filling Charging Cylinder

1.
Open control valve on refrigerant drum.

2.
Open valve on bottom of charging cylinder allowing

refrigerant to enter cylinder.

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

required to allow refrigerant to enter. When re-

frigerant reaches desired level (see "Air Condition-

ing System Capacities"), close valve at bottom of

cylinder and be certain bleed valve is closed

securely.

NOTE: It will be necessary to close bleed valve

periodically to allow boiling to subside to check

level in sight glass.

Installing Charging Station to System

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

2.
Connect high pressure gauge line to high pressure

gauge fitting. (See "Installing Gauge Set to Check

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

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

sure control (1) and allow refrigerant gas to hiss

from low pressure gauge line for three seconds,

then connect low pressure gauge line to low pressure

gauge fitting.

4.
System is now ready for performance testing.

Evacuating and Charging System

1.
Install charging station as previously described.

Refer to Figure 56 and 57 while performing the

following operation.

2.
Remove Low Pressure gauge line from compressor.

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

valves, and allow refrigerant gas to purge from

system. Purge slow enough so that oil does not

escape from system along with Refrigerant.

4.
When refrigerant flow stops, connect Low Pressure

gauge line to compressor.

5.
Turn on vacuum pump and open Vacuum Control

Valve (3).

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

inched of vacuum is obtained. Continue to run pump

for 15 minutes after the system reaches 28-29 inches

vacuum.

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

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

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

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

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

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

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

second evacuation is to be certain that as much con-

tamination is removed from the system as possible.

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

charging. Note reading on sight glass of charging

cylinder. If it does not contain a sufficient amount

for a full charge, fill to the proper leveL

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

close Vacuum Control Valve (3) and open Freon

Control Valve (4). Operating the heater and air

conditioner blower with the controls set for cooling

will help complete the charging operation.

NOTE: If the charge will not transfer com-

pletely from the station to the system, close

the high pressure valve at the gauge set, set

the air conditioning controls for cooling, check

that the engine compartment is clear of ob-

structions, and start the engine. Compressor

operation will decrease the low side pressure

in the system.

System is now charged and should be performance

tested before removing gauges.

CHECKING OIL

In the six cylinder compressor it is not recommended

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

ally, compressor oil level should be checked only where

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

might be caused by:

• A broken refrigerant hose.

• A severe hose fitting leak.

CHEVROLET CHASSIS SERVICE MANUAL

HEATER AND AIR CONDITIONING 1A-45

• A very badly leaking compressor seal.

• Collision damage to the system components.

As a quick check on compressor oil charge, with the

engine off, carefully crack open the oil drain plug on the

bottom of the compressor. If oil comes out, the com-

pressor has the required amount of oil To further check

the compressor oil charge, should the above test show

insufficient oil, it is necessary to remove the compressor

from the vehicle, drain and measure the oil.

Checking Compressor Oil Charge

1.
Run the system for 10 minutes at 500-600 engine

rpm with controls set for maximum cooling and

high blower speed.

2.
Turn off engine, discharge the system, remove

compressor from vehicle, place it in a horizontal

position with the drain plug downward. Remove the

drain plug and, tipping the compressor back and

forth and rotating the compressor shaft, drain the

oil into a clean container, measure and discard the

oiL

3.
a. If the quantity drained was 4 fluid oz. or more,

add the same amount of new refrigerant oil to

the replacement compressor.

b.
If the quantity drained was less than 4 fluid oz.,

add 6 fluid oz. of new refrigeration oil to the

replacement compressor.

c. If a new service compressor is being installed,

drain all oil from it and replace only the amount

specified in Steps 3a and 3b above.

d. If a field repaired compressor is being installed,

add an additional 1 fluid oz. to the compressor.

4.
In the event that it is not possible to idle the com-

pressor as outlined in Step 1 to effect oil return to

it, proceed as follows:

a. Remove the compressor, drain, measure and

discard the oil.

b.
If the amount drained is more than 1-1/2 fluid

oz.
and the system shows no signs of a major

leak, add the same amount to the replacement

compressor.

c. If the amount drained is less than 1-1/2 fluid oz.

and the system appears to have lost an excessive

amount of oil add 6 fluid oz. of clean refrigeration

oil to replacement compressor, 7 fluid oz. to a

repaired compressor.

If the oil contains chips or other foreign ma-

terial, replace the receiver-dehydrator and flush
or replace all component parts as necessary. Add

the full specified volume of new refrigeration oil

to the system.

5.
Add additional oil in the following amounts for any

system components being replaced.

Evaporator 3 fluid oz.

Condenser . . . . ... . . . . . . 1 fluid oz.

Receiver-Dehydrator ....... 1 fluid oz.

NOTE: When adding oil to the compressor, it

will be necessary to tilt the rear end of the

compressor up so that the oil will not run out

of the suction and discharge ports. Do not set

the compressor on the shaft end.

Adding Oil to the System

The system should be completely assembled and un-

charged before adding oil. Use only uncontaminated

refrigerant oil (525 viscosity) and add as follows:

1.
Connect the low pressure line from the gauge set

to the low pressure gauge fitting on the P.O.A.

valve (Four-Season) or low pressure fitting on the

compressor connector Mock (Universal System).

2.
Connect the high pressure line from the charging

station gauge set to the compressor muffler or high

pressure side of the connector block.

3.
Disconnect the high pressure line from the gauge set,

make certain that the line is clean, and place the

end in a graduated container.

4.
Pour enough refrigerant oil into the container so

that the required volume may be drawn into the

system by the high pressure hose.

5.
Close the high pressure valve at the gauge set,

and open the low pressure valve.

6. Operate the vacuum pump to drop the pressure within

the system and cause atmospheric pressure to force

oil through the high pressure line into the system.

When the oil level has dropped the required volume,

pull the line out of the oil container and continue

vacuum pump operation to force the oil contained

in the line into the system.

7.
Shut off the vacuum pump and connect ttye high

pressure line to the gauge set. Open the high

pressure valve and evacuate the system through

the high and low pressure sides of the system.

Complete the charging operation as outlined in Step

10 under "Evacuating and Charging System".

COMPONENT REPLACEMENT AND MINOR REPAIRS

REFRIGERANT LINE CONNECTIONS

"O"
Rings

Always replace the "O" ring when a connection has

been opened. When replacing the "O" ring, first dip it

in refrigeration oil. Always use a backing wrench on

"O"
ring fittings to prevent the pipe from twisting and

damaging the "O" ring. Do not overtighten. Correct

torque specifications are as follows:
Metal

Tube

O.D.

1/4

3/8

1/2

5/8

3/4
Thread and

Fitting

Size

7/16

5/8

3/4

7/8

1-1/16
Steel

Tubing

Torque*

13

33

33

33

33
Alum.

Tubing

Torque*

6

12

12

20

25

* Pound Feet

CHEVROLET CHASSIS SERVICE