1973 OPEL GT-R adding oil

REFRIGERANT COMPONENTS ALL MODELS96.23Figure 96-l 3 Basic Refrigerant Circuit
we get the heat-laden vapor outside, we can com-
press it with a pump. With enough pressure, we can
squeeze the heat out of “cold” vapor even in a warm
room. An ordinary.radiator will help us get rid of
heat.
By removing the heat, and making the refrigerant
into a liquid, it becomes the same as it was before, So,
we can run another pipe back into the cabinet and
return the refrigerant to the flask to be used over
again.
That is the way most mechanical refrigerators work
today. Now, let’s look at an air conditioning unit to
see how closely it resembles the refrigerator we have
just described.
Basic Air ConditionerWhen we look at an air conditioning unit, we will
always find a set of coils or a tinned radiator core
through which the air to be cooled passes. This is
known as the “evaporator” (Fig.
9B-14). It does the
same job as the flask of refrigerant we
spok.e about
earlier. The refrigerant boils in the evaporator. In
boiling, of course, the refrigerant absorbs heat and
changes into a vapor. By piping this vapor outside
the car we can bodily carry out the heat that caused
its creation.
Once we get vapor out of the evaporator, all we haveFigure 98.14 Evaporator Assembly
to do is remove the heat it contains. Since heat is the
only thing that expanded the refrigerant from a liq-
uid to a vapor in the first place, removal of that same
heat will let the vapor condense into a liquid again.
Then we can return the liquid refrigerant to the
evaporator to be used over again.
Actually, the vapor coming out of the evaporator is
very cold. We know the liquid refrigerant boils at
temperatures considerably below freezing and that
the vapors arising from it are only a shade warmer
even though they do contain quantities of heat.
Consequently, we can’t expect to remove heat from
sub- freezing vapors by “cooling” them in air tem-
peratures that usually range between 60 and 100
degrees heat refuses to
flow from a cold object
toward a warmer object.
But with a pump, we can squeeze the heat-laden
vapor into a smaller space. And, when we compress
the vapor, we also concentrate the heat it contains.
In this way, we can make the vapor hotter without
adding any heat. Then we can cool it in compara-
tively warm air.
That is the only responsibility of a compressor in an
air conditioning system (Fig.
9B-15). It is not in-
tended to be a pump just for circulating the refriger-
ant. Rather, its job is to exert pressure for two
reasons. Pressure makes the vapor hot enough to
cool off in warm air. At the same time, the compres-
sor raises the refrigerant’s pressure above the con-
densing point at the temperature of the surrounding
air so it will condense.
As the refrigerant leaves the compressor, it is still a
vapor although it is now quite hot and ready to give
up the heat that is absorbed in the evaporator. One
of the easiest ways to help refrigerant vapor dis-
charge its heat is to send it through a radiator- like
contrivance known as a condenser (Fig. 9B-16).
The condenser really is a very simple device having
no moving parts. It does exactly the same job as the
radiator in a typical steam-heating system. There,
the steam is nothing more than water vapor. In pass-
ing through the radiator, the steam gives up its heat
and condenses back into water.
The same action takes place in an air conditioning

9B-30 1973 OPEL SERVICE MANUAL
refrigerant penetrates to every nook and cranny of
the unit.
Among the many desirable properties of R-12, is its
stability under operating conditions. However, while
more stable than the other refrigerants under the
same conditions, it, too, can be caused to form harm-
ful acids which will eventually fail the system.OilOil is the most complex of all of the organic chemi-
cals. Its stability in a refrigerating system is depend-
ent upon the source of crude oil and its method of
refining. A good refrigerating oil must be free of
sludge and gum-forming substances and free of
harmful impurities, such as sulphur. It must also be
stabilized to resist oxidation and must have a high
degree of resistance to carbonization.
The chemical properties of the lubricating oil form
another very important consideration in the chemi-
cal stability within the system. Like the refrigerant,
it travels to every nook and cranny of the unit.
The factory obtains the finest oils which have been
refined from the most desirable
crudes. It is reproc-
essed at the factory before it is charged into a system
or poured into a container for resale. Its
voscosityand flash point are checked and it is forced through
many sheets of filtering paper.
Even the containers in which it is poured for resale
are processed. As you recive it for field service it is
the cleanest, dry&, and purest oil that is humanly
possible to make. Leaving the container uncapped
even for a few minutes allows the oil to absorb mois-
ture from the air. Many system failures have been
caused by chemical reactions which were started by
servicemen adding contaminated oil.
Desiccants (Dehydrating Agent)Over the years the industry has spent hundreds of
thousands of dollars in finding and developing
chemical substances which are suitable for use in
refrigerating systems. An ideal desiccant must have
the following characteristics:
I. High capacity.
2. High eficiency.
3. Low tendency to powder.
4. Absorb moisture without reacting chemically with
it.5. Allow refrigerant to flow through it with mini-
mum restriction.
6. Retain moisture at high temperature.This has been a difficult combination to find. While
some desiccants excel in several of the desirable char-
acteristics, they are unsatisfactor:y in others.
Activated Silica Alumina, used in current
receiver-dehydrators, is a most satisfactory desiccant. How-
ever, its ability to retain moisture is affected by its
temperature. As the temperature increases, its ability
decreases. This means that moisture which is re-
tained at a lower temperature may be put back into
the system at a higher temperature.
MAINTAINING CHEMICAL STABILITY IN THE
REFRIGERATION SYSTEMThe metal internal parts of the refrigeration system
and the refrigerant and oil contained in the system
are designed to remain in a state of chemical stability
as long as pure R-12 plus refrigeration oil is used in
the system. However, when abnormal amounts of
foreign materials, such as dirt, air or moisture are
allowed to enter the system, the chemical stability
may be upset (Fig. 9B-24).
Figure
98.24 System Contaminants
When accelerated by heat, these contaminants may
form acids and sludge and eventually cause the
breakdown of components within the system. In ad-
dition, contaminants may affect the temperature
pressure relationship of R-12, resulting in improper
operating temperature and pressures and decreased
efficiency
OF the system.
The following general practices should be observed
to maintain chemical stability in the system:
Whenever it becomes necessary to disconnect a re-
frigerant or gauge line, it should be immediately
capped. Capping the tubing will also prevent dirt and
foreign matter from entering.
Tools should be kept clean and dry. This also in-
cludes the gauge set and replacement parts.

REFRIGERANT COMPONENTS ALL MODELS9B- 31
When adding oil, the container should be exception-
ally clean and dry due to the fact that the refrigera-
tion oil in the container is as moisture-free as it is
possible to make it. Therefore, it will quickly absorb
any moisture with which it comes in contact. For this
same reason the oil container should not be opened
until ready for use and it should be capped immedi-
ately afte;r use.
When it is necessary to open a system, have every-
thing you will need ready and handy so that as little
time as possible will be required to perform the oper-
ation. Don’t leave the system open any longer than
is necessary.
Finally, after the operation has been completed and
the system sealed again, air and moisture should be
evacuated from the system before recharging.
THE PRIMARY CAUSES OF SYSTEM FAILURES
LeaksA shortage of refrigerant causes oil to be trapped in
the evaporator. Oil may be lost with the refrigerant
at point of leakage. Both of these can cause compres-
sor seizure.
Oil circulates in the system with the refrigerant; in
solution with the liquid and in globules with the
vapor. It leaves the compressor by the action of the
pistons and mixes with the refrigerant liquid in the
condenser. The oil then enters the evaporator with
the liquid and, with the evaporator properly flooded,
is returned to the compressor through the low pres-
sure line. Some of the oil returns as globules in the
vapor, but more important, it is swept as a liquid
along the walls of the tubing by the velocity of the
vapor. If the evaporator is starved, the oil cannot
return in sut?icient quantities to keep the compressor
properly lubricated.
High Temperature and PressureAn increase in temperature causes an increase in
pressure. This accelerates chemical instability due to
existing contaminants in the system, and initiates
chemical instability in clean systems. Other results
are brittle hoses,
“0” ring gaskets, and valve dia-
phragms with possible decomposition, broken com-
pressor discharge reeds, and seized compressor
bearings.
A fundamental law of nature accounts for the fact
that when a substance, such as a refrigerant, is in-
creased in temperature, its pressure is also increased.
Any chemical reactions caused by contaminants al-
ready in the system are greatly accelerated as the
temperature increases. A 15 degree rise in tempera-
ture doubles the chemical action. Even in a goodclean system, heat alone can start a chain of harmful
chemical reactions.
While temperature alone can cause the synthetic rub-
ber parts to become brittle and possibly to decom-
pose, the increased pressure can cause them to
rupture or blow.
As the temperature and pressure increases the stress
and strain on the compressor discharge reeds also
increases. This can result in broken reeds. Due to the
effect of the contaminants caused by high tempera-
ture and pressure, compressor bearings can be
caused to seize.
High temperature and pressure are also caused by air
in the system.
Air in the SYstemAir results from a discharged system or careless ser-
vicing procedures. This reduces system capacity and
efficiency and causes oxidation of oil into gum and
varnish.
When a leak causes the system to become dis-
charged, the resulting vacuum within the system will
cause air to be drawn in. Air in the system is a
non-condensable gas and will build up in the con-
denser as it would in an air compressor tank. The
resultant heat produced will contribute to the condi-
tions discussed previously.
Many systems are contaminated and also reduced in
capacity and efficiency by servicemen who either do
not know or are careless regarding proper servicing
procedures.
Too frequently, systems which have been open to the
atmosphere during service operations have not been
properly purged or evacuated. Air is also introduced
into the system by unpurged gauge and charging
lines. Remember that any air in the system is too
much air.
Poor ConnectionsHose clamp type fittings must be properly made.
Hoses should be installed over the sealing flanges and
with the end of the hose at the stop flange. The hose
should never extend beyond the stop flange. Locate
the clamp properly and torque as recommended. Be
especially careful that the sealing flanges are not
nicked or scored or a future leak will result.
When compression fittings are used, over tightening
can cause physical damage to the “0” ring gasket
and will result in leaks. The use of torque and back-
ing wrenches is highly recommended. When making
a connection with compression fittings, the gaskets
should always be first placed over the tube before

98-36 1973 OPEL SERVICE MANUALSPACER
17
RETAINER
RING
c Q
CLUTCHCOIL 8HOUSINGARING TO HEADTAINER RING
SHAFT NUT
CLUTCH DRIVEN
PLATE
BEARING TO PULLEYPULLEY BEARIN
RETAINER RINGCOIL 8HOUSING
CLUTCH DRIVEPLATIRETAINER RING
AND PULLEY ASSEMBLY
Figure 98-32
Magnetic Clutch and Pulley Assemblyis tack-welded to the inside of the shell. In addition,
an oil drain screw and gasket are located on the side
of the reservoir and are provided for draining or
adding of oil to system. To add oil, compressor must
be removed from car. The necessity to add oil should
only be required when the system has ruptured vio-
lently and oil has been lost along with refrigerant.
Under controlled conditions or slow leak conditions
it is possible to loose only a small amount of oil with
the refrigerant gas. The serial number, part or model
number, and rating of the compressor is stamped on
name plates located on top of shell.
12. Magnetic Clutch and Pulley Assembly
- The
magnetic clutch and pulley assembly (see Figure 9B-
32) together transmit power from the engine crank-
shaft to the compressor. The magnetic clutch is
actuated when the air conditioning temperature
switch and the fan switch located on the evaporator
cover assembly are closed. When the switches are
closed, the coil sets up a magnetic field and attracts
the armature plate (movable element of the clutch
driven plate). The armature plate portion of the
clutch driven plate moves forward and contacts the
friction surface of the pulley assembly, thereby me-
chanically linking the compressor to the engine. The
compressor will operate continuously whenever the
air conditioner clutch compressor switch and the fan
switch are closed. When one or both of the switches
are open the armature plate will be released due to
spring tension and move away from the pulley as-
sembly. This allows the pulley to rotate without driv-
ing the shaft. It should be noted that if the air
conditioner system was in use when the engine was
turned off, the armature plate may remain in contact
with the pulley due to residual magnetism. When the
engine is started the armature plate will separate
from the pulley assembly. The coil is rated at 3.85
ohms (85 degrees F.) and will draw 3.2 amperes at
12 volts D.C.Condenser
The condenser which is made of aluminum is locatedIN:ET
DESICCANT.
RECEIVERDEHYDRATOR
ASSEMBLY
FILTER
SCREEN
Figure 98-33 Receiver Dehydrator Assembly

98-46 1973 OPEL SERVICE MANUAL
shut off vacuum pump. Open refrigerant control
valve and allow some refrigerant to enter system.
Locate and repair all leaks.
7. After evacuating for 15 minutes, add l/2 lb. of
refrigerant to system. Purge this
l/2 lb. and reevacu-
ate for 15 minutes. This second evacuation is to be
certain that as much contamination is removed from
the system as possible.
8. 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, till to proper level.
9. Close low pressure valve on charging station.
Fully open station refrigerant control valve and al-
low all liquid refrigerant to enter system. When full
charge of refrigerant has entered system, turn off
refrigerant control valve and close both hand shut-
off valves.
10. If full charge of refrigerant will not enter system,
close high pressure control and refrigerant control
valves. Start engine and run at low idle with com-
pressor operating. Crack refrigerant control valve
and low pressure control on station. Watch low side
gauge and keep gauge below 50 psi by regulating
refrigerant control valve. Closing valve will lower
pressure. This is to prevent liquid refrigerant from
reaching the compressor while the compressor is op-
erating. When required charge has entered system,
close refrigerant control valve and close low pressure
control.
11. System is now charged and should be perform-
ance- tested before removing gauges.
Adding Refrigerant
The following procedure should be used in adding
small amounts of refrigerant that may have been lost
by leaks or while opening system for servicing the
compressor. Before adding refrigerent to replace that
lost by leaks, check for evidence of oil loss and add
oil if necessary.
This procedure will only apply if the air inlet temper-
ature is above 70 degrees F. at the condenser.
1. Remove caps from compressor gauge fittings.
Attach gauge set to gauge fittings, making sure
adapter (J- 5420) is between low pressure gauge hose
and suction gauge fitting, and J-9459 is between high
pressure gauge hose and discharge gauge fitting.
2. Start engine, turn air conditioning temperature
control knob to full cold position, blower switch to
Max Hi. Operate for ten
(IO) minutes at 2000 RPM
to stabilize system.
3. Observe the refrigerant through the sight glasscover of receiver-dehydrator with the system operat-
ing,
IO see if there are any bubbles evident.
a. If no bubbles are evident, then bleed system slowly
through the discharge valve until bubbles appear in
the receiver-dehydrator. Add 1 lb. of refrigerant as
explained under “Charging the
ISystem”.b. If bubbles are visible in the receiver-dehydrator
with the temperature control krlob in the full cold
position and the blower at MAX speed, it indicates
a partial or complete plug in a line, a shortage of
refrigerant, or both. Correct condition. Add refriger-
ant
u~ntil the sight glass clears, then add another 1 lb.
of refrigerant.
4. Attach flexible hose from center fitting of gauge
set loosely to refrigerant drum or on disposable can
valvxs. Open high and low pressure valves on the
gauge set slightly to purge pressure gauge lines of air.
Tighten fitting of refrigerant drum or can when satis-
fied ihat all air has been removed from gauge lines.
Close (clockwise) both hand shut-off valves or gauge
set.5. Partially charge system.
REFRIGERANT DRUM METHOD:
A. Place pail containing hot water that does not have
a temperature exceeding 125 degrees F. on scales,
place refrigerant drum in pa” containing water, note
weig,ht and only open low pressure valve on gauge
set.B. Start engine, turn temperature control knob to full
cold position and place blower switch in Max Hi.
Operate engine for 10 minutes at 2000 RPM to sta-
bilize system.
C. With compressor operating, slowly open valve on
refrigerant drum and allow refrigerant to flow into
system (through manifold gauge set) until liquid in-
dicator clears up and immediately shut off valve ai
gauge set or on refrigerant drum. Check weight of
refrigerant drum and pail of water. Then slowly open
valve on gauge set (or refrigerant drum) and add one
more lb. of refrigerant. Note total amount of refriger-
ant added.
DISPOSABLE CAN METHOD:
A. Make sure the outlet valve on the J-6271 valve is
fully clockwise and attach the J-6271 to a 1 lb. can
of refrigerant by backing off the valve from the top
of the retainer, slipping the valve onto the can and
turning the valve into the retainer until tight. DO
NOT accidentally open outlet valve during this oper-
ation, as turning the valve into the retainer punctures
the top of the can to make it ready for charging.
.

REFRIGERANT COMPONENTS ALL MODELS9a- 47
B. Connect center flexible line of gauge set to the
fitting on the valve.
C. Start engine, turn temperature control knob to full
cold position, set blower switch to Max Hi. Operate
engine for 10 minutes at 2000 RPM to stabilize sys-tem.D. With compressor operating, slowly open valve on
refrigerant can and allow refrigerant to flow into
system (through manifold gauge set) until liquid in-
dicator clears up and immediately shut off valve at
gauge set and on refrigerant can. Check weight of
can and valve assembly and record.
E. Add an additional 1 lb. of refrigerant by adding
refrigerant from the can just weighed until can is
empty. Attach another can and add refrigerant until
can and valve assembly weigh the same as recorded.
6. Close valves at refrigerant drum or
can,7. Test for leaks and make operational check of
system.
ADDING OIL TO THE SYSTEM (MAJOR
OVERHAUL)The oil in the refrigeration system does not remain
in the compressor during system operation, but cir-culates throughout the system. The compressor is
initially charged with 10 oz. of 525 viscosity oil.
After system has been in operation the oil content in
the compressor will vary depending on the engine
RPM and air conditioning load. At higher engine
RPM’s a lesser amount of oil will be retained in the
compressor reservoir. It is important that the total
system oil content does not vary from a total of10-l/2 oz. Excessive oil content will reduce cooling
capacity. Inadequate oil content may result in dam-
age to compressor moving parts.
The refrigeration system will not require adding of
oil unless there is an oil loss because of a ruptured
line, badly leaking compressor seal, replacement of
evaporator, compressor, receiver-dehydrator, or loss
due to a collision. Oil is generally added to the sys-
tem via the oil drain hole in the lower side of the
compressor for this condition. To add oil to the sys-
tem via the compressor, the compressor must be
removed. If no major loss of oil has occurred and a
component (condenser,receiver-dehydrator or
evaporator) is removed for servicing, the oil may be
added directly to the component. To add oil to a
component removed for servicing and when no ma-
jor loss has occurred, drain and measure oil in com-
ponent, then replace with a like amount. To add oil
to the system when a major loss of oil is evidenced,
or when the compressor is being serviced, remove
compressor, drain and measure oil, and replace oil
amount specified in the Oil Replacement Table.
OIL REP,‘LACEMENT TABLE
Condition
1. Major loss of oil and
a component (conden-
ser, receiver-dehydra-
tor, or evaporator)
has to be replaced.
Amount of Oil Drained
From Compressora. More than 4 oz.Amount of 525 Oil to Install
In Compressora. Amount drained from compressor,
plus amount for component
being replaced.
Evaporator
- Add 2 oz.
Condenser
- Add I oz.
Receiver-Dehydrator
- Add 1 oz.
b. Less than 4 oz.b. Install 6 oz., plus amount for
component being replaced as
shown above.
2. Compressor being
replaced with a
ser-vice replacement
compressor
- no major
oil loss.a. More than 1
l/2 oz.a. Same amount as drained from
compressor being replaced.
b. Less than 1
l/2 oz.b. Install 6 oz

98-56 1973 OPEL SERVICE MANUAL
oil cooler lines to lower radiator tank. It is essential
that no dirt enters the oil lines. When tightening oil
lines hold connectors on lower radiator tank with
pliers to avoid leakages. Ensure that no dirt enters oil
cooler. Torque to 11-15 Ibs. ft.
7. Install fan shroud.
8. Install upper radiator hose.
9. Install lower radiator hose and add collected coo-
lant.
All Opel
1900’s and Manta’s are provided with a
radiator initial fill of an anti-freeze solution contain-
ing corrosion inhibitor. The anti-freeze has either a
glycol or glycerin base and protects the engine
against freezing, down to minus 22 degrees F. (minus
30 degrees C.). Before the start of the cold season,
coolant must be checked with a hydrometer and if
necessary, brought to the necessary specific gravity
by adding anti-freeze. Anti-freeze added, must have
a glycol or glycerin base. As the specific gravities of
all anti-freeze solutions having a glycol or glycerin
base are practically the same, the hydrometer can be
used for all these types. Because of the tolerances of
the hydrometer, or slight differences in specific
gravity, variations of plus or minus 5 degrees can be
expected. Coolant must be checked at a temperature
of plus 68 degrees F. (plus 20 degrees C.).
IO. Install negative battery cable and air cleaner.
11. Charge system. Refer to CHARGING SYS-
TEM.
Figure 99.80 Location of Idler Pulley and Bracket
Assembly
- GTFigure 99.81 Idler Pulley and Bracket Assembly and
Support Bracket GT
REMOVAL AND INSTALLATION OF
COMPRESSOR. GT
I. Removenegative battery cable from battery.
Figure 98-82 Compressor Adapter Fitting, Ground
Wire. and Front and Rear Mounting Bolts
- GT
Figure 99.83
Elecirical Connector and Ground Wire
GT