OPEL GT-R 1973 Service Manual

9A-i2 1973 OPEL SERVICE MANUAL
Check that air doors and water temperature control
valve are operating properly.
Check for plugged heater core-backflush heater core
as necessary.TROUBLEInadequate defrosting action.
CAUSE AND CORRECTIONExamine heater-defroster door for proper operation.
Adjust bowden cable so that door is fully closed in
FULL DEFROST position.
Check that air hoses connecting to defroster outlets
are secure.
Check for air leaks around edges of heater air dis-
tributor housing. Seal leaks, as necessary, with bodysea@. Check for body air leaks and seal, as neces-
sary, with body sealer.
TROUBLEBlower inoperative.
CAUSE AND CORRECTIONCheck blower fuse. Replace, if necessary, fuse posi-
tion 4
- amperage 15.
Check wiring for open circuit. Correct, as required.
Inspect for defective component, (i.e., blower switch
or blower motor)
- replace or repair as necessary.
MAINTENANCE AND ADJUSTMENTS
CONTROL CABLE ADJUSTMENTAdjustment of control cables is accomplished by po-
sitioning of the jacket or sheath of the control cable,
as held by the clamps on the control assembly and
heater case or by loosening screws and slidingbowden wire to obtain desired door or water valve
position.
MAJOR REPAIR
REMOVING AND INSTALLING HEATER HOUSING
Removal1. Unscrew hood lock together with ground wire(ground wire only on vehicles with radio interference
suppression). See Figure 9A-33.
Figure 9A-33 Hood Lock Attachments
2. Unscrew heater housing cover.
3. Pull hose of windshield washer system off jet and
take jet out of housing cover.
4. Unscrew bowden control wire from heater valve.
5. Unscrew heater housing from dash panel and pull
it off carefully. See Figure 9A-34.
Figure 9A-34 Heater Housing Attachments
6. Remove water hoses from heater core and pull
heater core out of heater housing. See Figure
9A-35.

Figure SA-35 Heater Core
Installation
1. Apply sealing compound between heater housing
and dash panel.
2. Install heater core into heater housing and attach
water hoses. See Figure 9A-35.
3. Instaii heater housing to dash panel. S,ee Figure9A-44.
4. Install bowden control wire to heater valve.
5. Install windshield washer jet into housing cover
and attach hose.
6. Install heater housing cover, and seal with a seal-
ing compound.
7. Install hood lock, together with
grc’und wire
(ground wire only on vehicles with radio interference
suppression).
REMOVING AND INSTALLING
DEFROSTE+lOUTLETS
Removal
1. Pull out heater switch lever. See Figure 9A- 36.
2. Remove instrument cover.
3. Unscrew bowden control wires from heater valve
and air distributor housing and pull out heater con-
trols.
4. Remove glove compartment.
HEiATER SYSTEM - OPEL 1900 - MANTA9A. 13Figure SA-36 Removing Heater Switch Lever
5. Remove radio.
6. On right side, viewed in driving direction, remove
air distributor housing attaching screws. See Figure9A-37
Figure SA-37 Air Distributor Housing Attaching
SCWWS7. On left side, viewed in driving direction, remove
upper attaching screw through opening for heater
control housing and lower attaching screw below
instrument panel. See Figure 9A-38.
8. Pull air distributor housing off dash panel

9A-14 1973 OPEL SERVICE MANUAL
upper attaching screw through opening for heater
control housing and lower attaching screw below
instrument panel. See Figure 9A.-38.5. On right side, viewed in driving direction, install
air distributor housing attaching screws. See Figure9A-37.
6. Install radio.
7. Install glove compartment.
8. Install bowden control wires to heater valve and
air distributor housing.
9. Install instrument cover.
10. Install heater switch lever.
Figure 9A-38 Upper Attaching Screw
9. Pull defroster outlets downwards and remove out-
lets through glove compartment opening. See Figure9A-39.
REMOVAL AND INSTALLATION OF HEATER
CONTROL HOUSING
Removal1. Remove instrument panel cover
- refer to operat-
ion,
IRemoving and Installing Instrument Housing.
2. Remove two sheet metal screws for control hous-
ing attachment. See Figure 9A-40.
Figure 9A-39 Removing Defroster Jets
Installation
1. Apply sealing compound between air distributor
housing and dash panel.
2. Install defroster outlets, securing with two (2)
clips at the instrument panel. See Figure 9A-39.
3. Install air distributor housing to dash panel,
4. On left side, viewed in driving direction, installFigure 9A-40 Control Housing Attaching Screws
3. In engine compartment, detach bowden control
wire from heater valve. See Figure 9A-41.
4. Detach bowden control wire from air distribution
flap. See Figure 9A-42.
5. Pull wires off blower switch. See Figure 9A- 43.

HEATER SYSTEM. OPEL 1900. MANTA9A- 15
Figure 9A-4 1 Bowden Wire Attachment
Figure SA-42 Control Wire
to Distribution? DoorAttachmentA
- Yellow Wire
B
- Grey Wire
C
- Brown Wire
6. Remove heater control housing.
Installation1. Install heater control housing,
2. Install wires onto blower switch. See Figure 9A-
53.Figure 9A-43 Blower Switch Wires
A
- Yellow Wire
B
- Grey Wire
C
- Brown Wire
3. Attach bowden control wire to air distribution
flap. See Figure 9A-42.
4. In engine compartment, attach bowden control
wire to heater valve. See Figure 9A-41.
5. Install two (2) sheet metal screws for control hous-
ing attachment. See Figure 9A-40.
6. Install instrument panel cover.
7. Adjust bowden control wires.
REMOVAL AND INSTALLATION OF HEATER
MOTOR
1. In engine compartment, remove five (5) shroud
cover attaching screws. See Figure 9A-44.
2. Carefully remove cover
3. Pull water hose off windshield wiper jet.
4. Disconnect wires to heater motor. For this pur-
pose, disconnect multiple plug connection on left
side of shroud. See Figure 9A-45.
5. Remove three (3) heater motor attaching screws.
See Figure 9A-46.
6. Take off motor.

9A-16 1973 OPEL SERVICE MANUAL
Figure 9A-44 Shroud Cover AttachmentsFigure 9A-46 Heater Motor Attaching Screws
Figure 9A-45 Heater Motor Wires
InstallationFigure 9A-47 Sealing Shroud
1. Install heater motor, attaching with three (3)
screws. See Figure 9A-46.
2. Connect multiple plug on left side of shroud. See
Figure 9A-45.3. Seal shroud cover front and rear contacting areas
with sealing cement. See Figure 9A-47.
4. Install shroud cover, attaching with five (5)
screws.SPECIFICATIONS
EngineRecommended Coolant
..........................................................................Ethylene-Glycol Base
ThermostatOpensAt(Degrees)
F.......................................................................................189Cooling System Capacity (With Heater)
..........................................................................6 Qt.
Blower Motor Type
......................................................................................................12 VDC
Blower Fan Type
..............................................................................................................Blade
Numberof FanBlades
..............................................................................................................7

REFRIGERANT COMPONENTS
ALL MODELS
CONTENTS
Subject
DESCRIPTION AND OPERATION:
FundamentalPrinciplesofRefrigeration..................
Description of Air Conditioning Components
..........DIAGNOSIS:
GeneralInformation..........................................................
Leak Testing
System1........................................................
Functional Testing System............................................
DiagnosisGuide..................................................................
MAINTENANCE AND ADJUSTMENTS:
General Service Information and
Safety Precautions;........................................................
Charging
andDischargingSystem..............................
AddingOiltotheSystem................................................
Flushing the System........................................................
MAJOR REPAIR:
Removal and Installation Compressor
Opel1900.Manta........................................................
GT
........................................................................................
Removal and Installation Condenser
Receiver-Dehydrator
Assembly
- GT.................................................................
Receiver-Dehydrator
.Opel 1900.Manta................GT..................................................
Removal and Installation Evaporator and
Expansion Valve
- Opel 1900.Manta....................
GT......................................................
Disassembly and Reassembly of Clutch Drive
Plate
andShaftSeal....................................................
Disassembly and Reassembly of Pulley Assembly
and Coil and Housing Assembly..............................
Disassembly and
Reaissembly of Internal
Parts of Compressor and Leak Testing
Compressor..............................................................................
SPECIFICATIONS:
Specifications........................................................................Page No.
9B-18
98-33
98-38
98-39
98-39
90-40
98-41
98-41
9B-47
98-48
98-48
98-56
98-62
90-4990-58
98-52
98-59
98-63
98-67
98-69
98-82REFRIGERANT COMPONENTS ALL MODELS
96-17

98.18 1973 OPEL SERVICE MANUAL
DESCRIPTION AND OPERATION
FUNDAMENTAL PRINCIPLES OF REFRIGERATION
We all know what air conditioning does for us, but
very few understand how or why it works. An air
conditioner is functionally very similar to a refrigera-
tor, so let’s take a look at refrigeration. A refrigerator
is a simple mechanism which, surprisingly enough,
works quite a bit like a tea-kettle boiling on a stove.
That may sound far-fetched, but there is more
similarity between the two than most of us would
suspect. In fact, a modern refrigerator can make ice-
cubes and keep food cool and fresh only because a
liquid called the refrigerant boils inside the freezer.
Of codrse everyone knows a boiling tea-kettle is
“hot” and a refrigerator is “cold”. However, this is
where most of us are apt to get confused. We usually
think of “cold” as a definite, positive condition. Ac-
tually though, there is no such thing as “cold”. The
only way we can define it is in a rather negative sort
of way by saying “cold” is simply the lack of heat
just as darkness is the lack of light. We can:t make
things cold directly. All we can do is remove some
of the heat they contain and they will become cold
as a result. And that is the main job of any ice-box
or refrigerator. Both are simply devices for removing
heat.
All substances contain some heat. Theoretically, the
lowest temperature that any substance could obtain
is 459 degrees Fahrenheit below Zero. This may be
called “Cold”, and anything warmer than this con-
tains heat. Since man has never succeeded in getting
all the heat out of an object, we must think about the
transfer of heat from one object to another when
talking about controlling temperatures.
Figure
96-1 Transfer of Heat
Transfer of HeatThe only thing that will attract heat is a colder ob-ject.
:Like water, which always flows down-hill, heat
always flows down a temperature scale
- from a
warm level down to a colder one. When we hold our
hands out toward the fireplace, heat flows from the
hot fire out to our cold hands (Fig.
9B-1). When we
make a snowball, heat always flows from our warm
hands to the colder snow. In an ice-box, the ice al-
ways is colder than the stored food, so heat naturally
is drawn out of the warm food by the colder ice.
Measurement of HeatEveryone thinks he knows how heat is measured.
Thermometers are used in most: homes. Whenever
we speak of temperature from now on, we will mean
Fahrenheit. They can tell how hot a substance is, but
they can’t tell us everything about heat.
Figure
98-2 Applied Temperature Alone is Not the
Sole Measurement of Heat
When we put a tea-kettle on a stove, we expect it to
get hotter and hotter until it finally boils. All during
the process, we can tell exactly how hot the water is
by means of a thermometer (Fig.
9B-2). However,
our thermometer will show us that the flame is just
as hot when we first put the tea-kettle on the stove
as it is when the water finally boils. Why doesn’t the
water boil immediately then? Also, why does it take
longer to boil a quart of water than a cupful? Obvi-
ously temperature isn’t the only measurement of
heat.
Even though heat is intangible, it can be measured by
quantity as well as intensity. It is recognized that
thermometers indicate only the intensity of heat. The
unit for measuring quantity of heat is specified as
that amount necessary to make 1 pound of water 1
degree warmer (Fig.
9B-3). We call this quantity of
heat a British Thermal Unit. Often it is abbreviated
to Btu.
Perhaps we can get a better idea of these two charac-

REFRIGERANT COMPONENTS ALL MODELS9s. 19
Figure 98.3 Effect of One B.T.U. on One
Pc’und of
water
teristics of heat if we think of heat as a sort of color-
ing dye. If we add one drop of red dye to a glass of
water, it will turn slightly pink. Another drop will
make the water more reddish in color (Fig.
9B-4).The more drops of dye we add, the redder the water
will get. Each drop of dye corresponds to 1 Btu and
the succeedingly deeper shades of red are like in-
creases in temperature.
Figure
98-4 Addition of B.T.U. Heats Water
It may seem a little puzzling to talk about beat in a
story on air conditioning but, when you stop to
think about it, we are handling heat exclusively. Al-
though we ordinarily think of an air conditioner as
a device for making air cold, it doesn’t do that di-
rectly. What it does is take heat away from the in-
coming air and transfer that heat outside the vehicle.
We know now that cold is nothing more than the
absence of heat, and that heat always flow from a
warm object to a colder one. We also have
:a clearer
idea of how heat is measured.
From everything we’ve learned about heat
EO far, it
seems to behave in a perfectly normal manner. Yetsometimes heat will disappear without leaving a sin-
gle clue.
Ice vs. Water for CoolingEtery once in a while in the old days, the ice-man
would forget to refill the ice-box. Occasionally, as the
last sliver of ice melted away, somebody would come
up with a bright idea. He would remember that the
water in the drain-pan always felt ice-cold when he
had emptied it other times. So, he would get the
thermometer out and check its temperature. Sure
enough, it usually was about as cold as the ice. Why
not put the drain-pan back in the ice compartment
to keep things cold until the iceman returned the
next day
It was a good idea. but it never worked. For some
strange reason the ice-box never stayed cold. The
drain water soon got quite warm and in a couple of
hours, the butter in the ice-box would begin to melt,
the milk would start to sour, and the vegetables
would wilt.
Why did this happen? The drain water was only a
few degrees warmer than the ice yet it didn’t draw
nearly as much heat out of the stored foods. How-
ever, the difference between the behavior of cold
drain water and ice is the real secret as to how any
refrigerator works and we can easily learn the an-
swer by using an ordinary thermometer.
When we put a drain pan full of cold water into the
ice compartment, we expect the heat to flow from the
warm foods to the colder water. Remember, that
heat always flows from a warm object to a colder
object and when we add heat to water, it gets
warmer. Each Btu of heat added to a pound of water
makes it one degree warmer.
Figure 98.5 Melting Ice Remains at 32 Degrees

98-20 1973 OPEL SERVICE MANUAL
If we were to put a thermometer in the cold drain
water, we would see the temperature gradually creep
upwards. That is to be expected because heat is flow-
ing into the cold water making it warmer. Before
long the water would be as warm as the stored foods.
Then the water could no longer attract heat because
heat will not flow from one warm object to another
equally warm object. Since we no longer can draw
heat out of the foods we no longer are cooling them.
Now, let’s see what happens when we put ice instead
of cold water into the ice-box. This time, we’ll set the
thermometer on top of the ice (Fig. 9B-5). When wefirst look at the thermometer, it reads 32 degrees. A
couple of hours later, we open the ice compartment
door. The ice block is smaller because some of the ice
has already melted away
- but the thermometer still
reads 32 degrees. Again, still later, even more of the
ice has melted, yet the termometer continues to read
32 degrees. So long as any ice remains, no matter
how much of it has melted away, the temperature of
the ice stays right at 32 degrees.
All this time the ice has been soaking up heat, yet it
never gets any warmer no matter how much heat it
draws from the stored food. On the other hand, the
cold drain water got progressively warmer as it
soaked up heat. Why is it the addition of heat will
make water warmer yet won’t raise the temperature
of ice above the 32 degrees mark? If we till one
drinking glass with ice and another with cold water,
and put both glasses in the same room where they
could absorb equal amounts of heat from the room
air, we will find it takes much, much longer for the
ice to melt and reach room temperature than it did
for the water in the other glass to reach the same
temperature. Obviously, most of the heat was being
used to melt the ice. But it was the heat that appar-
ently disappeared or went into hiding because if
couldn’t be located with a thermometer. To best de-
scribe this disappearing heat, scientists turned to
Latin for the right word. They chose the word “la-
tent” which means hidden.
Latent Heat
So latent heat is nothing more nor less than hidden
heat which can’t be found with a thermometer.
What happens to the latent heat? Where does it
disappear to? At first it was thought it was in the
water that melted from the ice. But that wasn’t ex-
actly the right answer because, upon checking water
temperature as it melts from ice, it will be found that
it is only a shade warmer than the ice itself. It is not
nearly warm enough to account for all the heat the
ice had absorbed. The only possible answer is that
the latent heat had been used up to change the ice
from a solid into a liquid.
Many substances can be either a solid, or a liquid, ora gas. It just depends on the temperature whether
water for example was a liquid, or a solid (ice), or gas
(steam) (Fig.
9B-6).Figure 99-6 Temperature Determines State of Water
If we put some water in a tea-kettle, set it over a tire
and watch the thermometer as the water gets hotter
and hotter, the mercury will keep rising until the
water starts to boil. Then the mercury seems to stick
at the 212 degrees mark. If we put more wood on the
fire, despite all the increased heat, the mercury will
not budge above the 212 degree mark (Fig.
9B-7).Figure 98.7 Boiling Water Never Exceeds 2 12
DegreesEven though many housewives won’t believe it, no
matter how large or hot you make the flame, you
can’t make water hotter than 2 12 degrees. As a liquid
changes into a gas, it absorbs abnormally great
amounts of heat without getting any hotter. Here is
another instance where heat disappears.
Now we have two different kinds of latent heat,
which are quite alike. To keep their identities sepa-
rate, the first one is called latent heat of fusion. Since
fusion means the same as melting, it is a good de-
scriptive name. The other kind is called latent heat
of vaporization because‘ that means the same as
evaporation.
It may seem as though we have drifted into a story

REFRIGERANT COMPONENTS ALL MODELSSE- 21
about heat instead of refrigeration. But in doing so,
we have learned how a simple ice-box works. It’s
because the magic of latent heat of fusion gives ice
the ability to soak up quantities of heat without get-
ting any warmer.
Therefore, since it stays cold, it can continue to draw
heat away from stored foods and make them cooler.
The latent heat of vaporization can be an even better
“magnet” because it will soak up even more heat.
Whenever we think of anything boiling, we instinc-
tively think of it being very hot. However, that’s not
true in every case. Just because water
boi1.s at 212
degrees doesn’t mean that all other substances will
boil at the same temperature. Some would have to be
put into a blast furnace to make them bubble and
give off vapor. On the other hand, others will boil
violently while sitting on a block of ice.
And so each substance has its own particular boiling
point temperature. But regardless of whether it is
high or low, they all absorb unusually large quanti-
ties of heat without getting any warmer when they
change from a liquid into a vapor.
Consequently, any liquid that will boil at a tempera-
ture below the freezing point of water, will make ice
cubes and keep vegetables cool in a mechanical re-
frigerator.
Figure
9B-10 Simple R-12 Refrigerator
Refrigerant - 12Refrigerant-12 is used in the air conditioning system
and boils at 21.7 degrees below zero. Maybe that
doesn’t mean very much until we picture a flask of
R-12 sitting at the North Pole boiling away just like
a tea-kettle on a stove. No one would dare pick up
the flask with his bare hands because, even though
boiling, it would be so cold and it would be drawing
heat away from nearby objects so fast that human
flesh would freeze in a very short time. If we were toput a flask of R-12 inside a refrigerator cabinet, it
would boil and draw heat away from everything sur-
rounding it (Fig.
9B-10). So long as any refrigerant
remained in the flask, it would keep on soaking up
heat until the temperature got down to 21.7 degrees
below zero.
Now we can begin to see the similarity between a
boiling tea-kettle and a refrigerator. Ordinarily we
think of the flame pushing heat into the tea-kettle.
Yet, it is just as logical to turn our thinking around
and picture the tea-kettle pulling heat out of the
flame. Both the tea-kettle and the flask of refrigerant
do the same thing they draw in heat to boil
although they do so at different temperature levels.
There also is another similarity between the ice-box
and the mechanical refrigerator. In the ice-box, wa-
ter from melting ice literally carried heat out of the
cabinet. In our simple refrigerator, rising vapors do
the same job.Rdsing
Our R-l 2Water is so cheap that we could afford to throw it
away. But R-12, or any other refrigerant, is too ex-
pensive just to let float away into the atmosphere. If
there was some way to remove the heat from the
vapor and change it back into a liquid, it could be
returned to the flask and used over again (Fig. 9B-
11).There is a way, and that is where we find the biggest
difference between the old ice-box and the modern
refrigerator. We used to put in new ice to replace that
lost by melting. Now we use the same refrigerantover and over again.
Figure 9B-1 1 Re-Using Refrigerant