HEATER AND AIR CONDITIONING 1A-47
are certain procedures, practices and precautions that
should be followed to prevent costly repairs, personal
injury or damage to equipment. For this reason it is
strongly recommended that the preceding information in
this section be studied thoroughly before attempting to
service the sytem.
Great emphasis must be placed upon keeping the sys-
tem clean. Use plugs or caps to close system components
and hoses when they are opened to the atmosphere. Keep
your work area clean.
In removing and replacing any part which requires
unsealing the refrigerant circuit the following operations,
which are described in this section, must be performed
in the sequence shown.
1.
Purge the system by releasing the refrigerant to the
atmosphere.
2.
Remove and replace the defective part.
3.
Evacuate and charge the system with R-12.
CAUTION: Always wear protective goggles
when working on refrigeration systems. Goggles
J-5453 are included in the set of air conditioning
special tools. Also, beware of the danger of
carbon monoxide fumes by avoiding running the
engine in closed or improperly ventilated
garages.
FOREIGN MATERIAL IN THE SYSTEM
Whenever foreign material is found in the system,
it must be removed before restoring the system to
operation.
In the case of compressor mechanical failure, perform
the following operations:
1.
Remove the compressor.
2.
Remove the receiver-dehydrator and discard me
unit.
3.
Flush the condenser to remove foreign material
which has been pumped into it.
4.
Disconnect the line from the receiver-dehydrator
at the inlet connection of the expansion valve. Inspect
the inlet screen for the presence of metal chips
or other foreign material. If the screen is plugged,
replace it. Reconnect the line to the expansion
valve.
5. Install a new receiver dehydrator.
6. Install the replacement compressor.
7. Add the necessary quantity of oil to the system (one
fluid ounce because of receiver-dehydrator replace-
ment plus the quantity needed for the replacement
compressor—see Checking Compressor Oil Charge
under Checking Oil.
8. Evacuate and charge the system.
9. Check system performance.
CONDENSER
Chevrolet
Replacement
1.
Remove the hood catch and hood catch - grille
support.
2.
With the system purged of refrigerant, disconnect
the inlet and outlet hose clamp connections and the
condenser to radiator support attaching screws.
3.
Remove the condenser from the vehicle.
NOTE:
If it is to be reused, cap or tape the
receiver-dehydrator inlet and outlet connections
at once.
4.
Install new condenser, position the assembly and
install the radiator support to condenser attaching
screws and replace all line connections.
5. Replace the hood catch and grille support and its
attaching bolts.
6. Replace the hood catch.
7. Evacuate, charge and check the system. Add one
fluid oz. refrigerant oil after installing a new
condenser.
Chevelle and Camaro
Replacement
1.
Remove the hood lock catch support and catch.
2.
With the system purged of refrigerant, disconnect
the inlet and outlet hose clamp connections and the
condenser to radiator support attaching screws.
3.
Remove the condenser from the vehicle.
NOTE:
Cap or tape the inlet and outlet con-
nections at once.
4.
Install new condenser, position the assembly and in-
stall the radiator support to condenser attaching
screws and replace all line connections.
5. Evacuate, charge and check the system. Add one
fluid oz. refrigerant oil after installing a new
condenser.
Chevy II
Replacement
1.
Purge the refrigerant from the system.
Fig.
59—Condenser Mounting (Chevrolet and Chevelle)
CHEVROLET CHASSIS SERVICE MANUAL
HEATER AND AIR CONDITIONING 1A-48
Fig.
60-Condenser Mounting (Chevy II)
2.
Remove the bumper, bumper filler panel, grille,
grille support, hood lock catch support and catch as
described in Section 11, "Chassis Sheet Metal".
3.
Disconnect connectors at condenser inlet and outlet
tubes and remove screws attaching refrigerant line
holding clips to the condenser baffle.
4.
Remove bolts attaching condenser through radiator
' support and slide condenser to the left and out of
vehicle.
5. Reverse these steps to reinstall new condenser.
6. Evacuate and charge the system. Add one fluid oz.
of refrigerant oil after installing a new condenser.
Corvette
Replacement (Production Engine)
1.
Remove the hood from the car, first scribing the
hinge attachment location.
2.
Purge the system of refrigerant.
Fig.
61—Condenser Mounting (Cdrnaro)
Fig.
62—Condenser Mounting (Corvette)
3.
Disconnect the inlet line connection at the condenser
inlet and the outlet line at the receiver-dehydrator.
Cap the receiver-dehydrator immediately.
4.
Remove the screws attaching the condenser to the
radiator support and carefully lift the unit from the
car.
5. Remove the receiver-dehydrator from the old con-
denser and install it, using a new "O" ring, on the
new condenser.
6. Set new condenser in place on the radiator support
and install the attaching screws, torquing them to
20 lbs. ft.
7. Make the inlet and outlet connections, using new
"O"
rings, and torque 13 lbs. ft.
8. Evacuate, charge and check the system. Add one
fluid oz. of refrigerant oil after installing a new
condenser.
Replacement (Optional Engine)
Replacement procedure remains much the same for the
installation supplied with the optional engine except for
the location of the receiver-dehydrator. Follow the steps
given above except that the outlet line must be removed
at the receiver outlet. (See Figure 64.)
RECEIVER-DEHYDRATOR
The receiver-dehydrator should be replaced if it has
been damaged through an accident or if it leaks or be-
comes restricted or clogged. Do not attempt to repair
the receiver-dehydrator.
The receiver-dehydrator is merely a moisture collect-
ing device and a refrigerant storage area and is the least
likely component of the system to cause a malfunction.
If at any time when examining the compressor oil,
moisture is found or there is an indication of moisture
at the expansion valve needle, the receiver-dehydrator
should be replaced as follows (fig. 63):
NOTE:
If the receiver-dehydrator is to be re-
used, cap the inlet and outlet connections
immediately. When installing a receiver-
dehydrator, do not uncap the connections until
CHEVROLET CHASSIS SERVICE MANUAL
HEATER AND AIR CONDITIONING 1A-49
CHEVROLET
CHEVELLE
CHEVY II
CAMARO
the last possible moment. Be certain that the
direction of flow is correct before connecting
the pipes.
Chevrolet, Chevelle, Chevy II, and Camaro
Replacement
1.
Remove the receiver inlet and outlet connections and
the two receiver to fender skirt attaching screws.
2.
Carefully remove the receiver-dehydrator from the
vehicle.
3.
Replace the new receiver~dehydrator assembly in
the vehicle and install all attaching screws and re-
frigerant lines.
4.
Add one fluid oz. refrigerant oil, evacuate and charge
the system.
Corvette
Replacement
1.
Purge the system of refrigerant.
2.
Disconnect the "O" ring inlet
hose clamp outlet connection
openings.
3.
Remove the receiver-dehydrator to radiator support
bracket screws (production engine) or receiver-
dehydrator to condenser bracket screws (optional
engine) and remove the unit from the car.
4.
Install the new receiver-dehydrator applying 30 in.
lbs.
torque to the attaching screws.
connection and the
and tape the hose
NOTE:
Do not uncap the new receiver-
dehydrator until the last instant before
installation.
5.
2.
3.
Fig.
63—
Receiver-Dehydrator Mounting (Chevrolet,
Chevelle/ Chevy II, Camaro)
Connect the high pressure lines at the inlet (use a
new "O" ring and torque connection to 13 ft. lbs.)
and outlet (torque screw to 25 in. lbs.).
6. Add one fluid oz. refrigerant oil, evacuate, charge
and check the system.
Sight Glass Replacement-All Vehicles
If damage to the sight glass should occur, a new sight
glass kit should be installed. The kit contains the sight
glass,
seal and retainer. (See Figure 65.)
1.
Purge system.
Remove the sight glass retainer nut using a screw
driver and remove old glass and seal.
Install the new glass and seal and retainer nut, being
careful not to turn the nut past the face of the hous-
ing. To do so may damage the "O" ring seal.
4.
Evacuate and recharge the system.
EVAPORATOR
Chevrolet and Camaro Four-Season System
The evaporator and blower case assembly is designed
so that the core may be removed without the need for
removing the entire unit from the vehicle. Instead,
only the side cover must be removed.
Removal and Installation of Entire Assembly
1.
Remove the inlet line at the expansion valve and the
suction throttling valve outlet connection.
2.
Remove the electrical connector from the blower
motor.
CHEVROLET CHASSIS SERVICE MANUAL
HEATER AND AIR CONDITIONING 1A-53
Fig.
70—Wiring and Vacuum Lines—Four-Season (Camaro)
Installation
1.
Connect the expansion valve to the refrigerant pipes.
Attach the capillary bulb to the evaporator.
2.
Attach the evaporator to the- case. Attach the inlet
and outlet pipes clamps.
3.
Assemble the case halves. Insert the capillary tube
from the thermostatic switch between the fins as
shown in Figure . Attach the cover plate to the
case.
4.
Mount the unit to the dash and connect the refrigerant
lines.
5.
Evacuate and charge the system. If a new evaporator
was installed, add three fluid ounces of refrigerant
oil to the system before charging.
6. Test system operation.
Chevy II All-Weather System
Removal
Under
the Hood
1.
Purge the refrigerant from the system.
2.
Remove the refrigerant hoses from the evaporator
inlet and outlet connections extending through the
special grommet in the dash panel and into the
engine compartment.
3.
Remove the screw, nut, spacer bracket and grommet
from the outlet connection pipes.
Within the Car
4.
Remove the glove box, ash tray and ash tray
retainer.
5.
Reach through the glove box door to disconnect the
air conditioning "on" door bowden cable (fig. 75).
6. Remove the two shield attaching screws and shield
(A, fig. 76) which covers the lower right evaporator
bracket-to-blower bracket attaching screw (B, fig.
76),
then remove this screw.
7.
Behind the lower left side of ihe evaporator, remove
the evaporator bracket-to-heater distributor bracket
attaching screw (C, fig. 76).
8. Reaching through the glove box door and ash tray
openings, remove the two nuts and washers (D,
fig.
76) attaching the evaporator assembly studs to
the lower instrument panel flange and reinforcement.
9. Disconnect the drain hoses and carefully pull the
evaporator unit toward the rear of the vehicle.
10.
Disconnect wiring connectors (see fig. 77) as nec-
essary and remove the evaporator unit from the
vehicle.
Gore and/or Expansion Valve Replacement
A defective unit must be replaced since repairs should
never be made on the evaporator core. Before replacing
the core, however, check to be sure that any leaks pres-
sent are not located at the hose connections or expansion
valve connections. The following procedure assumes that
the evaporator unit has been removed from the vehicle
as outlined above.
CHEVROLET CHASSIS SERVICE MANUAL
HEATER AND AIR CONDITIONING 1A-56
BLACK & RED
IGNITION—-y^****
SWITCH -"A
/
BLOWER LEAD—^^^
RESISTOR—-" \^<
ASM.
f'
i
'fu^^^^A^^^^^r"G^OUH£>
WIRE
^^
k4
^EVAPORATOR HARNESS
' EVAPORATOR & BLOWER ASM.
Fig.
73—Underdash Wiring—Universal System (Typical)
evaporator outlet pipes. Locate the bracket about
1/2" from the dash panel.
12.
Replace the inlet and outlet hoses and hose clamp
connections.
13.
Evacuate and charge the system. Add three fluid oz.
refrigerent oil after installing a new core.
14.
Check system performance.
Corvette
Replacement (Fig. 78)
1.
Purge the system of refrigerant.
2.
Drain the engine radiator. Then remove the radiator
supply tank from its brackets, the heater water
valve and vacuum line from the firewall, and the
heater hoses from the core pipes. Carefully fold the
hoses,
valve and tank away from the evaporator
case.
3.
Remove the right hand hood lock support.
SCREW DRIVER
(NARROW BLADE) T£
GROOVE
A. Insert screw driver in
tang toward terminal
B. Pry tang back out to
when reinstalled into
RMINAL
\ CONNECTOR
TANG
groove & press
to release.
insure locking
connector.
Fig.
74—Terminal Removal—Universal System
4.
Disconnect the expansion valve equalizer line con-
nection and the evaporator oil bleed line from the
POA.
5.
Disconnect the evaporator outlet to POA inlet
connector.
6. Remove the POA bracket to evaporator case attach-
ing bolts. Then carefully move the valve and its
outlet hose away from the evaporator case.
Fig.
75-Cable Removal-All Weather
CHEVROLET CHASSIS SERVICE MANUAL
HEATER AND AIR CONDITIONING 1A-62
2.
Insert the evaporator assembly into the outlet case
half and mount the evaporator, thermostatic switch,
and cable to the case.
3.
Install the face plate to the case and install control
retaining nuts and knobs.
4.
Assemble the case halves and mount the evaporator
pipe clamp.
5. Install the evaporator assembly as previously
described under EVAPORATOR.
BLOWER ASSEMBLY
Four-Season System
Chevrolet and Camaro
Removal
1.
Disconnect battery ground cable.
2.
Remove the right front fender and skirt assembly.
3.
Disconnect the motor wire at the flange connector.
4.
Disconnect the rubber air cooling tube from the
motor.
5. Remove the motor to case attaching screws and re-
move the blower assembly. If the sealer acts as an
adhesive, pry the assembly carefully away from the
6. Remove the blower from the motor shaft.
Fig.
86—Blower Assembly—Four-Season (Chevrolet,
Chevelle, Camaro)
Installation
1.
Mount the blower to the motor shaft with the open end
of the blower away from the motor.
2.
Mount the assembly to the case with the attaching
screws.
3.
Connect the rubber tube and blower wire to the
motor.
4.
Replace the right front fender and skirt assembly.
5. Connect battery ground cable.
Chevelle
The blower assembly (fig. 86) is mounted to the dash
panel and contains the outside air-recirculated air
diverter door, the heating-cooling diverter door, the air
conditioning relay and resistor, the compressor actuating
switch, and the blower motor.
Replacement
1.
Disconnect the blower motor "hot" wire at the con-
nector and the ground lead on the Chevrolet.
2.
Detach the rubber cooling tube from the blower as-
sembly and remove the five bolts attaching the
blower motor to the blower assembly.
3.
Remove the motor and fan, disassemble fan from
motor and install on a new motor. If, because of
engine accessories, hoses restrict lifting the blower
assembly from the engine compartment, remove
blower from motor and lift units out separately.
Assemble replacement units under the restricting
hoses.
4.
Reinstall motor and fan into blower assembly. Re-
place cooling tube, ground wire and connect hot wire
to connector.
5. Check blower operations.
Corvette
Replacement
1.
Remove the radiator overflow tank and brackets and
pull the tank out of the way as far as the length of the
heater hose will permit.
2.
Disconnect the electrical connector and the rubber
air inlet tube from the blower motor.
3.
Remove the five blower flange to case attaching
screws and carefully remove the blower motor and
drum assembly.
4.
Remove the blower drum assembly and reinstall on
a new blower motor.
5. Replace the blower motor and drum assembly in the
case and reinstall all screws, hoses and electrical
connections.
All-Weather System
Chevy II
Removal
Under the Hood
1.
Purge the refrigerant from the system.
2.
Drain the radiator.
3.
Remove the refrigerant hoses at the evaporator
pipes.
4.
Remove the evaporator pipe clamp and grommet.
5. Remove three nuts from the blower case studs which
pass through the firewall.
6. Remove heater hoses from core tubes.
CHEVROLET CHASSIS SERVICE MANUAL
HEATER AND AIR CONDITIONING 1A-63
Under Dash
7. Remove ash tray and retainer, and glove box.
8. Remove blower case to air inlet adapter bracket
retaining screw.
9. Remove screw attaching air distributor to firewall.
10.
Remove nuts retaining evaporator case to lower lip
of dash. Withdraw evaporator drain tubes.
11.
Lower complete heater - air conditioning assembly.
12.
Remove screw retaining blower case to air distrib-
utor and separate them.
13.
Remove blower to case attaching screws. Disconnect
motor wire and remove blower assembly.
14.
Remove blower from motor shaft.
Installation
1.
Assemble blower to motor shaft.
2.
Mount motor in blower case and connect wire.
3.
Assemble blower case to air distributor and install
retaining screw.
4.
Lift the complete assembly into place and install
attaching screws and nuts.
5. Replace ash tray retainer and tray and glove box.
6. Replace nuts (engine side of dash) on heater case
studs and connect heater hoses.
7. Replace evaporator pipe clamp and grommet.
8. Replace the refrigerant hoses.
9. Evacuate and charge the refrigeration system and
refill the cooling system.
10.
Check system performance.
Universal Blower Assembly
Removal
1.
Remove the universal unit from its dash mounts.
2.
Remove the cover plate and separate the upper and
lower case halves. Remove blower motor mounting
strap screw and swing strap outward.
3.
Remove blower assembly. Loosen the blower wheel
setscrews and remove the wheels from the motor
shaft. . ' .
Fig.
88-Air Inlet Assembly (Chevrolet)
Installation
1.
Install the blower wheels on the motor so that the
lower blades curve toward the firewall side of the
unit when the motor is placed in the case. Tighten
the setscrews.
2.
Place the motor in the bracket with the electrical
connector side of the motor to the right side of the
bracket. Attach the mounting strap.
3.
Assemble the case halves and attach the cover plate.
4.
Remount the unit to the dash.
Fig.
87—Blower Assembly—Universal System
Fig.
89—Air Doors (Camaro)
CHEVROLET CHASSIS SERVICE
HEATER AND AIR CONDITIONING 1A-64
Fig.
90—Evaporator Wiring (Corvette)
AIR INLET VALVE
Four-Season System
Chevrolet
Figure 88 illustrates the vacuum valve which controls
the air inlet operation of the Four-Season System.
A vacuum tank and check valve is used to assure that
the air door will not change its position due to variations
in engine vacuum.
Camqro
Figure 89 illustrates the outside air inlet door assem-
bly, and the door in the kick pad which admits reeir-
culated air to the system.
BLOWER AND EVAPORATOR ASSEMBLY
(Corvette)
Replacement
1.
Remove the evaporator core as outlined under
"Evaporator Core Replacement".
2.
Remove the blower motor as outlined under "Blower
Motor Replacement".
3.
Remove the heater and air conditioning distributor
as outlined under "Air Distributor Duct Removal".
4.
Remove the remaining nuts attaching the blower
and evaporator assembly and the cover assembly
to the studs on the -firewall.
5. Replace the components removed by reversing the
removal, procedure.
AIR DISTRIBUTOR ASSEMBLY
AND OUTLET DUCTS
Four Season System
Chevrolet and Chevelle
Figures 92 through .95 illustrate the air distributor and
outlet ducts as used in the Chevrolet, Chevelle, Camaro,
and Corvette.
Corvette
Right Outlet Duct
Removal
1.
Remove the clamp screw at the inner end of the
outlet duct and loosen the clamp.
2.
Remove the screw and lock washer attaching the
duct outer mounting tab to the body hinge pillar
brace.
3.
Pull the duct and clamp down and away from the
distributor assembly. Disconnect the courtesy light.
4.
The duct extension assembly may now be removed
if desired as well as the deflector assembly. See
Figure 95.
AIR COND.
PULL
AIR PULL- DEFROSTER
FAN PULL HOT PULL
Fig.
91—Corvette Four-Season Controls
CHEVROLET CHASSIS SERVICE MANUAL