1973 OPEL GT-R radiator cap

HEATER SYSTEM. OPEL 1900. MANTA9A- 11air is attained, as the water does not cool down in the
second part of the core.
A Water Outlet
B Water Inlet
The center lever actuates the two-stage blower mo-
tor.Lever positions:
Left to Center
- Motor Switched Off
Right of Center
- Lo Blower
Right
- Hi Blower
The lower lever opens and closes the air door which
channels the air flow to either the lower heater out-
lets or to the defroster outlets.
In the left lever position, the air inlet is closed. Up
to the center position, the air is directed
t,o the lower
heater outlets.
When moving the lever from center position towards
the right, the air flow to the lower
heatezr outlets is
reduced and increased to the defroster
csutlets.With the lever in its right position, the air is directed
to the defroster outlets only. For windshield defrost-
ing, all levers have to be moved to the right.
FUNCTION OF THE HEATER AND VENTILATION
SYSTEMThe engine hood is provided with slots in front of the
windshield. The air is directed through the slots into
the heater housing located in the engine compart-
ment, flows into the air distributor housing, and
from there to the lower heater outlets and,/or defros-
ter outlets, depending on the position of the control.
The two-stage blower motor is arranged in the heater
housing above the heater core and actuated by the
center control. The blower motor draws in the air
entering through the slots, blows the air through the
heater core into the air distributor housin:?, and from
there to the lower heater outlets and/or defroster
outlets, depending on the position of the lower con-
trol. See Figure 9A-32.
The heater valve regulates the flow of coolant
through the heater core, thereby varying
t:he temper-
ature of the air flow past the core.
The ventilation of vehicle interior is completed by a
draft-free air circulation pattern. Vent
slots are ar-
ranged below the back window which
are: connected
through channels to the rear quarter
iside panel.
From here, the inside air escapes into
the! open. TheFigure
9A-32 Air Flow
head wind (caused by the car traveling down the
road) promotes this process so that there is always
fresh air in vehicle interior.
On the Model 54 Station Wagon, there will be no air
outlets in the rear. For adequate flow-through type
ventilation, it will be necessary to open a rear win-
dow.Aside from the fresh air admission through the
heater system, two fresh air inlet nozzles are ar-
ranged in the center of the instrument panel. These
nozzles can be turned to direct the air flow in the
desired direction. In addition, rotary flaps allow the
regulation of the entering air or to shut off the air
completely.
These nozzles admit unheated fresh air only and
operate independent of the heater and defroster sys-
tem.
DIAGNOSIS
HEATER SYSTEM TROUBLE DIAGNOSIS
TROUBLETemperature of heated air at outlets too low.
CAUSE AND CORRECTIONCheck radiator cap for proper sealing action. Re-
place, if necessary.
Check for adequate coolant supply. If level is down,
correct cause of coolant loss and refill radiator.
Inspect hose for kinks. Relieve kink or replace hoses.
Check thermostat operation by measuring tempera-
ture of coolant at radiator. Temperature should be
within 5 degrees F. of thermostat rated value (189
degrees F.).

REFRIGERANT COMPONENTS ALL MODELS
99.37
in front of the radiator so that it receives a high
volume of air flow. Air passing over the condenser
absorbs the heat from the high pressure gas and
causes the refrigerant to condense into a high pres-
sure liquid.Receiver. DehydratorThe receiver-dehydrator is located in the engine
compartment. The purpose of the receiver dehydra-
tor is two fold: the unit insures a solid column of
liquid refrigerant to the expansion valve at all times,
and also absorbs any moisture in the system that
might be present. A bag of desiccant (moisture ab-
sorbing material) is provided to absorb moisture. A
sight glass (see Figure 9B-33) permits visual check-
ing of the refrigerant flow for bubbles or foam. The
continuous appearance of bubbles or foam above an
ambient temperature of 70 degrees F. usually indi-
cates an inadequate refrigerant charge. Bubbles or
foam appearing at ambient temperatures below 70
degrees F. do not necessarily indicate an inadequate
charge and may appear even when the system is
operating properly. A filter screen in the unit pre-
vents foreign material from entering the remainder
of the system.
Expansion ValveThe expansion valve is mounted on the evaporator
core inside the passenger compartment. The function
of the expansion valve is to automatically regulate
SCREEN
lLCl98.30
Figure 98-34 Expansion Valvethe flow of refrigerant into the evaporator. The ex-
pansion valve is the dividing point in the system
between the high and low pressure liquid refrigerant.
A temperature sensing bulb is connected by a capil-
lary tube to the expansion valve (see Figure
9B-34).The temperature sensing bulb (clamped to the outlet
pipe on the evaporator) measures the temperature of
the evaporator outlet pipe and transmits the temper-
ature variations to the expansion valve (see Figure
9B-34). The capillary tube and bulb are tilled with
carbon dioxide and sealed to one side of the expan-
sion valve diaphragm.
An increase in temperature will cause the carbon
dioxide in the bulb and capillary tube to expand,
overcoming the spring pressure and pushing the dia-
phragm against the operating pins (see Figure 9B-
34). This in turn will force the valve off its seat.
When the refrigerant low pressure gas flowing
through the outlet pipe of the evaporator becomes
more than 6 degrees higher or warmer than the tem-
perature at which it originally began to vaporize or
boil, the expansion valve will autmotatically allow
more refrigerant to enter evaporator. If the tempera-
ture of the low pressure gas decreases to less than 6
degrees above the temperature at which it originally
began to vaporize or boil, the expansion valve will
automatically reduce the flow of refrigerant. Thus,
an increase or decrease in the flow of refrigerant
through the evaporator will result in an increase or
decrease in the cooling by the evaporator. The tem-
perature, humidity and volume of the air passing
over the evaporator affects the rate of absorption of
heat by the evaporator. As the ambient temperature
bulb calls for more or less refrigerant will increase or
decrease. When the air is very warm, the heat trans-
fer from the air to the refrigerant is great and a
greater quantity of refrigerant is required to maintain
the temperature at the evaporator pipe at the prede-
termined value. Conversely, cool days will result in
less heat transfer and thereby require lesser quanti-
ties of refrigerant to maintain the predetermined
temperature of the evaporator outlet pipe.
EvaporatorThe function of the evaporator is to cool and
dehumidify the air flow in the passenger compart-
ment. The evaporator assembly consists of an alumi-
num core enclosed in a reinforced plastic housing.
Two (2) water drain ports are located in the bottom
of the housing. Two refrigerant lines are connected
to the side of the evaporator core: one at the bottom
and one at the top. The expansion valve is attached
to the lower (inlet) pipe, the outlet pipe is attached
to the upper pipe. The temperature sensing bulb of
the expansion valve is clamped to the outlet pipe of
the evaporator core. The high pressure liquid refrig-
erant, after it is metered through the expansion
valve, passes into the evaporator core where it is
allowed to expand under reduced pressure. As a re-
sult of the reduced pressure the refrigerant begins to

98.40 1973 OPEL SERVICE MANUAL
2. Interconnect manifold and gage set (J-5725-01),
gage charging lines (J-5418) and gage adapters
(J-5420) to air conditioning system as shown in Figure
9B-40.3. Place transmission in “Park” for automatics and
in neutral for manuals. Apply hand brake.
4. Turn blower switch to the “Hi” position.
5. Turn temperature switch to “Max” position.
6. Run engine at 2000 RPM for ten (10) minutes with
car doors and windows closed and the hood up. Place
a high volume industrial type fan in front of radiator
if head pressure should exceed 250 psi and also at
high ambients to bring the pressures to within the
limits specified in the Functional Charts in Division
V.In the case of the Opel 1900 and the Manta, a ther-
mometer should be placed in a position to read the
temperature of the air discharging from the right-
hand A/C outlet. In case of the GT, a thermometer
should be placed in a position to read the tempera-
ture of the air discharging from the left-rear A/C
outlet.
HEATER-AIR CONDITIONER REFRIGERANT
CIRCUIT TROUBLE DIAGNOSIS GUIDE
Insufficient Cooling (Check Air Flow)
Normal Air Flow (Inspect system for visual defects.
Run functional tests.)
Discharge Air
- Normal Temp Check for air leaks
through dash, car body, windows, or from heater or
ventilators.
Discharge Air
- High Temp Check sight glass for
foaming and compressor clutch for engagement.
No Compressor Clutch Engagement Check connec-
tions at clutch switch, harness connectors, and check
clutch switch.
No Foaming Compare evaporator pressure to that
on functional test table.
Foaming System is probably low on refrigerant.
Check for leaks, repair, evacuate, and charge. If
foaming still occurs, check for restriction in refriger-
ant lines between condenser and receiver dehydrator.
Evaporator Pressure Normal Compare head pres-
sure to pressure on functional test table.
Evaporator Pressure Low Ice may be forming on
evaporator. Low volume of air discharging at A/C
outlet after system has been running above idle con-dition
,for approximately 15-30 min.utes. Discharging
air gradually elevating in temperature. Check expan-
sion valve. If valve isn’t permitting flow of liquid,
this will be indicated by a warm pipe out of the
evaporator. This may be caused by: 1) Clogged or
Plugged inlet screen in the expansion valve; 2)
Broken capillary line; or 3) Discharged temperature
bulb. If the valve is okay, the pipe out of the evapora-
tor will be cold.
Evaporator Pressure High Check the expansion
valve to determine if themobulb is making good con-
tact and is properly insulated. Operate engine at 2000
RPM with maximum air conditioning setting. If
evaporator pressure remains high, feel suction line.
If line feels frosty or extremely
(cold with relative
high ambient conditions, then partially cover the
condenser to obtain head pressures from 265 psi to
280 psi maximum. If evaporator pressure rises above
30 psi, change the expansion valve.
Also, check if compressor may be the cause due to
some internal or external mechanical trouble which
prevents reduction of pressure. Check for external
troubles, slipping belt, bad clutch and/or pulley, or
improper clutch engagement, before investigating
the compressor internally.
Head Pressure High Check for the following: Con-
denser air flow low, air in system, excessive refriger-
ant in system, restriction in condenser.Head.PressureLowRestriction in flow of refrigerant
to evaporator, or expansion valve plugged or defec-
tive.
Low Air Flow (Check blower operation and
evaporator. Check operation of controls.)
Ice BIocking Evaporator Run functional test. If
evaporator pressure is low, ice may form on evapora-
tor and reduce air flow.
Evaporator Pressure Low Ice may be forming on
evaporator. Low volume of air discharging at A/C
outlet after system has been running above idle con-
dition for approximately 15-30 minutes. Discharging
air gradually elevating in temperature. Check expan-
sion valve. If valve isn’t permitting flow of liquid,
this will be indicated by a warm pipe out of the
evaporator. This may be caused by: 1) Clogged or
plugged inlet screen in the expansion valve; 2)
Broken capillary line, or 3) Discharged temperature
bulb. If the valve is okay, the pipe out of the evapora-
tor will be cold.BlowerNot OperatingCheck for the following: Fuse
blown, blower switch defective, wire broken or loose
connection, poor ground connection, or blower mo-
tor defective.

REFRlGEdANT COMPONENTS ALL MODELS96-49Figure 96.50 Sheet Metal Cover Removed
5. Unplug compressor clutch electrical plug, and
remove idler pulley bracket assembly and ground
wire. See Figure 9B-5 1. Radiator hose is removed forphotographic reasons only.
(Figure 98.52 Location of Compressor Mounting
,
Support Bolts Opel 1900 Manta
I
Figure 98-5 1 Location of Idler Pulley, Bracket and
Ground Wire Opel 1900
- Manta
6. After system is completely discharged, remove
refrigerant hoses from compressor adapter fitting
and cap hoses and adapter fitting to keep contami-
nants from entering.
7. Support compressor from underneath and
remove three (3) compressor mounting support boltsand support bracket. Carefully lower compressor.
See Figure
9B- 52. During removal, maintain the
compressor position so that the sump is downward.
Do not rotate compressor shaft.
1: Support compressor from underneath and install
into position from under car. Insure that compressor
haS sutXcient oil charge.
2, Install three (3) compressor mounting support
bolts. See Figure
9B-52.I
3! Install compressor support bracket. Torque boltsto
?O lb.ft. See Figure 9B-53.
4.: Install idler pulley fan belt, bracket assemblyan8 ground wire. Plug
‘In compressor clutch electri-
cal! plug. See Figure
9B-54.
5! Install refrigerant hoses and evacuate system.
Refer to EVACUATING THE. SYSTEM.
6.’ While system is being evacuated install sheet
m&l cover. See Figure 9B-50.
7.1 Install air cleaner and heat pipe.
S! Install negative battery cable and charge system.
Se: CHARGING THE SYSTEM.
REMOVAL AND INSTALLATION OF
REtiEWEFt-DEHYDRATORAS:EMBLY
- OPEL 1900 MANTA
I
R~l!lOV~lI1.’ Discharge system. Refer to DISCHARGING
THE SYSTEM.

SubjectPage Number
Subject Page Number
o,,e, 1900 & Manta .....................1H-59
GT..................................lH-63
intake Manifold, 1.9L Engine
..........:.....6A-12
R
Radiator
JRadiator All Models .,.
Radio
66-32
Joint,
Ball
adder.; ...............................3A-7
dower...............................3A-7
K
Antenna Trimmer Adjustment GT
Antenna Trimmer Adjustment
Opel 1900
& Manta
Removal and Installation Opel 1900
& Manta
Removal and Installation GT
Trouble Diagnosis GT
.,.
Trouble Diagnosis -Opel 1900 &Manta
Reverse Clutch
Rings, Piston,
1.9L Engine
Rocker Arm Assembly.
1.9L Engine..
9C-1 06
9C-1 10
Keys and Locks ..........................OA-1
L
Low Servo Cover .........................7c-100
Lubrication
Engine Oil Change Interval ................OC-7
Oil Viscosity Chart. .....................
OC-7
Fluid Capacities........................OC-5
Lubrication System, Engine .................6A-4
9C-1 11
9c-107
9c-105
9c-109
7c-103
6A-19
6A-12
s
M
Mainshaft Assembly 4.Speed
Manual Transmission ....................
78-26
Manifold
Intake ...............................
6A-12
Exhaust ..............................
6A-12
Master
Cdlinder, Brake.....................5A-2
Model
D&ignation (Body Style)
.............. OA-2
Mountings. Engine, GT ....................
28-6
Opel 1900 & Manta
.......................28-6
0
Oil Chan& Interval ........................OC-7
Oil Filter: Engine
.........................OC-7
Oil Flow Circuits, Automatic Transmission .....7C-64
Oil
Pan. Engine ..........................6A-10
Oil Pump Engine.........................
6A-26
Oil Pump Transmission ....................
7C-103
Oil Recommendations Engine. ..............
OC-7
Oil Strainer-Transmission..................7C-99
Oil Viscosity Chart ........................
OC-7
Opel Emission Control System
(OECS)
Specifications..........................6F-64
Service Procedures......................6F-63
Trouble Diagnosis ......................
6F-62
P
Parking Brake............................5C-33
Piston, Pin Rings ..........................
6A~lS
Planetary Gear Set ........................
7C-118
Power Unit Brake ........................
5A-5
Propeller Shaft ...........................
4A-2
Pump, Oil Engine........................
6A-26 Sequence for Transmission Diagnosis
..........
7C-81
Service ProceduresClutch..................7A~5
Shift Linkage Adjustments
4.Speed Manual ........................78-19
3.Speed Automatic .....................7C~93
Shock Absorber, Rear
All Series .............................
3F-51
Spark Plug Specifications ...........................
66-68
Clean &Adjust. ........................
lC-22
Installation............................lC-22
Wires................................lC~21
Specifications
Engine ................................
6A-27
Front Wheel Alignment ....................
3C~22
Speedometer Installation
Opel1900&Manta.....................1 l-68
GT..................................11-70
Spring
Rear SuspensionAll Series ..............
:............3F-52
Front Suspension
Opel 1900
& Manta ...................3A~l6
GTO Opel ..........................
3A15
Starting Motor
Description ............................
1 E-1 0
Specifications .............:............1 B-1 7
Repairs
..................:............18-13
Removal..............................1 B-l 3
Steering Columns
Service Procedures -Opel 1900 &Manta ....
3E-36
Service Procedures
- GT ...._............3E-44
Steering Gear Adjustment. .....
:............3D-27
Steering Gear Disassembly and
Redssembly.....3D-30
Steering Gear Removal and Install&ion ........
30-28
Steering Linkage ..........................
38-19
Suspension
Front................................3A-2
Rear .................................
3F-51
,