OPEL 1900 1973 Service Manual

98-32 1973 OPEL SERVICE MANUAL
inserting it in the connection. Another precaution -inspect the fitting for burrs which can cut the
“0”ring.
Restrictions
Restrictions may be due to powdered desiccant or
dirt and foreign matter. This may result in starved
evaporator and loss of cooling, or a seized compres-
SOT.When the amount of moisture in a system sufti-
ciently exceeds the capacity of the desiccant, it can
break down the desiccant and cause it to powder.
The powder passes through the dehydrator screen
with the refrigerant liquid and is carried to the ex-
pansion valve screen. While some of it may pass
through the valve screen into the evaporator, it may
quickly build up to cause a restriction.
Due to the fact that sufftcient oil can not be returned
to the compressor, it may seize.
Dirt
Dirt, which is any foreign material, may come from
cleaner residues, cutting, machining, or preserving
oils, metal dust or chips, lint or dust, loose rust,
soldering or brazing fluxes, paint or loose oxide
scale. These can also cause seized bearings by abra-
sion or wedging, discharge and expansion valve fail-
ure, decomposition of refrigerant and oil, or
corrosion of metal parts.
CorrosionCorrosion and its by-products can restrict valve and
drier screens, rough bearing surfaces or rapid fatigu-
ing of discharge reeds. This can result in high tem-
perature and pressure, decomposition or leaks. In
any event, this means a wrecked compressor.
From this, we can see the vicious circle that can be
produced in a refrigerating system to cause its fail-
ure. Corrosion can be the indirect cause of leaks, and
leaks can be the direct cause of corrosion. We can
also see the important role we as servicemen play in
maintaining chemical stability.
The major cause of corrosion is moisture.
Moisture
Moisture is the greatest enemy of refrigerating sys-
tems. Combined with metal, it produces oxide, Iron
Hydroxide and Aluminum Hydroxide. Combined
with R-12 it produces Carbonic acid, Hydrochloric
acid, and Hydrofluoric acid. Moisture can also cause
freeze-up of expansion valve and powdered desic-
cant.Although high temperature and dirt are responsible
for many difficulties in refrigerating systems, in most
instances it is the presence of moisture in the system
that accelerates these conditions. It can be said,themfore, that moisture is the greatest enemy of all.
The acids that it produces, in combination with both
the metals and the refrigerant, cause damaging
COT-
rosion. While the corrosion may not form as rapidly
with R-12 as with some other refrigerants, the even-
tual formation is as damaging.
If the operating pressure and temperature in the
evaporator is reduced to the freezing point, moisture
in the refrigerant can collect at the orifice of the
expansion valve and freeze. This temporarily re-
stricts the flow of liquid causing erratic cooling.
As previously mentioned, moisture in excess of the
desiccant’s capacity can cause it to powder.
YOU SHOULD KNOW AND REMEMBER..That the inside of the refrigerat,ion system is com-
pletely sealed from the outside world. And if that
seal remains broken at any point
- the system will
soon be destroyed. That complete and positive seal-
ing of the entire system is vitally important and that
this sealed condition is absolutely necessary to retain
the chemicals and keep them in a pure and proper
condition.
That all parts of the refrigeration system are under
pressure at all times, whether operating or idle, and
that any leakage. points are continuously losing re-
frigerant and oil.
That the leakage of refrigerant can be so silent that
the complete charge may be lost without warning.
That refrigerant gas is heavier than air and will rap-
idly drop to the floor as it flows from a point of
leakage.
That the pressure in the system may momentarily
become as high as 400 lbs. per square inch, and that
under such pressure the molecules of refrigerant are
forced out through the smallest opening or pore.
That the compressor is continually giving up some
lubricating oil to the circulating refrigerant and de-
pends upon oil in the returning refrigerant for con-
tinuous replenishment. Any stoppage or major loss
of refrigerant will therefore be fatal to the compres-
SOT.That the extreme internal dryness of a properly proc-
essed system is a truly desert condition, with the
drying material in the receiver holding tightly on to
the tiny droplets of residual moisture.

REFRIGERANT COMPONENTS ALL MODELS99- 33
That the attraction of the drying material for mois-
ture is so powerful that if the receiver is left open,
moisture will be drawn in from the outside air.
That just one drop of water added to the refrigerantwill start chemical changes that can result in corro-
sion and eventual breakdown of the chemicals in the
system. Hydrochloric acid is the result of an R-12
mixture with water.
That the smallest amount of air in the refrigeration
system may start reactions that can cause malfunc-
tions.
That the drying agent in the receiver-dehydrator is
Activated Silica Alumina (silica-gel).
That
the inert gas in the expansion valve capillary
line is carbon dioxide.
DESCRIPTION OF AIR CONDITIONING
COMPONENTS
Compressor
The compressor is located in the engine compart-
ment. The purpose of the unit is to draw the low
pressure,gas from the evaporator and compress this
gas into a high temperature, high pressure gas. This
action will result in the refrigerant having a higher
temperature than the surrounding air.
The
cortipressor is of basic double action piston de-
sign. Three horizontal double acting pistons make up
a six cylinder compressor (See Figure
9B-162). The
pistons operate in
l-1/2 inch bore and have a l-1/8
inch stroke. A
wash plate keyed to the shaft drives
the pistons. The shaft is belt driven through a mag-
netic clutch and pulley arrangement. An oil pump
mounted at the rear of the compressor picks up oil
from the
botto’m of the compressor and lubricates the
bearings’and other internal parts of the compressor.
Reed type valves at each end of the compressor open
or close to control the flow of incoming and outgoing refrigerant. Two gas tight passages interconnect
chambers of the front and rear heads so that there is
one common suction port, and one common dis-
charge port. The internal parts of the compressor
function, as follows:
1. Suction Valve Reed Discs and Discharge Valve
Plates
_ The two suction valve reed discs and two
discharge valve plates (see Figure
9B-25) operate in
a similar but opposite manner. The discs are com-
posed of three reeds and function to open when the
pistons are on the intake portion of their stroke
(downstroke), and close on the compression stroke.
The reeds allow low pressure gas to enter the cylin- ders. The discharge valve plates also have three
reeds, however, they function to open when the pis- tons are on the compression portion of their stroke
(upstroke), and close on the intake stroke. High pres-
sure gas exits from discharge ports in the discharge
valve plate. Three retainers riveted directly above the
reeds on the valve plate serve to limit the opening of
the reeds on the compression stroke.
SUCTION VALVE
DISCHARGE-VALVE PLATES
Figure
98-25 - Compressor Suction Valve Reed Discs
and Discharge Valve Plates
2. Front and Rear Heads - The front and rear heads
(Figure
9B-26) serve to channel the refrigerant into
and out of the cylinders. The front head is divided
into two separate passages and the rear head is di-
vided into three separate passages. The outer passage
on both the front and rear heads channels high pres-
sure gas from the discharge valve reeds. The middle
passage of the rear head also contains the port open-
ing to the superheat switch cavity. This opening in
the rear head permits the superheat switch to be
affected by suction gas pressure and suction gas tem-
perature for the operating protection of the compres-
sor. The inner passage on the rear head houses the
oil pump inner and outer rotors. A Teflon sealing
material is bonded to the sealing surfaces separating
the passages in the rear head.
“0” rings are used to
affect a seal between the mating surfaces of the heads
and the shell. The front head suction and discharge
passages are connected to the suction and discharge
passages of the rear head by a discharge tube and
suction passage in the
body of the cylinder assembly.
A screen located in the suction port of the rear head
prevents foreign material from entering the circuit.
3. Oil Pump
- An internal tooth outer rotor and
external tooth inner rotor comprise the oil pump.
The pump works on the principle of a rotary type pump. Oil is drawn up from oil reservoir in underside
of shell through the oil inlet tube (see Figure
9B-27)

98-34 1973 OPEL 3ERVlCE MANUAL
9B-23Figure
98.26 Compressor Front and Rear Heads
and circulated through the system via a 3/16 inch
diameter oil passage through the shaft center and
also four 5/64 inch diameter holes drilled perpen-
dicular to the shaft. The inner rotor is driven by the
shaft.TUBE
Figure
98-27 Compressor Oil Flow
4. Shaft and
Gash Plate Assembly - The shaft andwash plate assembly (see Figure 9B-162) consists of
an elliptical plate positioned obliquely to the shaft.
As the plate and shaft rotate, the surface of the plate
moves to and fro lengthwise relative to the centerline
of the shaft. This reciprocating motion is transmitted
to the pistons which contact the surface of the wash
plate. A woodruff key locks the wash plate onto theshaft. The wash plate and shaft are serviced as an
assembly. The shaft is driven by a pulley when the
magnetic clutch is energized. A needle thrust bearing
and
L mainshaft bearing support the shaft horizon-
tally and vertically.
5. Needle Thrust Bearing and Races
- Two needle
thrust bearings, each“sandwiched” between two
races are located on either side of the wash plate
hub. The front needle thrust bearing and races pro-
vide 0.010” to 0.015” clearance between the top of
the pistons and the rear side of the front suction valve
reed disc (see Figure
9B-28). The rear needle thrust
bearings and races provide 0.0005” to 0.0015” clear-
ance between the hub of the wash plate and the rear
hub of the rear cylinder. Races of various thicknesses
are provided for service replacement to achieve re-
quired clearances when rebuilding units.
6. Cylinder Assembly and service Pistons (Factory
installed pistons are ringless) -The cylinder assembly
(front cylinder and rear cylinder) is serviced only as
a matched set. Alignment of the two halves is main-
tained by two dowel (locater) pins.
The double ended pistons are made of cast alumi-
num. There are two grooves on each end of the ser-
vice piston. The outer grooves will receive a piston
ring. The inner grooves act as oil scraper grooves to
collect any excess oil. Two oil return holes are drilled

REFRIGERANT COMPONENTS ALL MODELS9s. 35
THRUST UNITSHOES ARE USED
CONTROLS PISTONTO GIVE
HEAD CLEARANCE
.0005 TO .OOlOTOTAL\CLEARANCE
THRUST UNIT CONTROLSRUNNING CLEARANCE.0005 TO .0015
9B-25Figure 98-28 Compressor Needle Thrust Bearings and
into the scraper grooves and allow oil to drain back
into the reservoir.
7. Shoe Discs
- The shoe discs are made of bronze
and act as a bearing between the ball and the wash
plate. An oil circulation hole is provided through the
center of each shoe for lubrication purposes. These
shoes are of various thicknesses and are provided in
0.0005 inch increments. Ten sizes are available for
service replacement. A basic “zero” shoe size is
available’ for preliminary gauging procedures when
rebuilding a cylinder assembly.
8. Suction Passage Cover-The suction passage cover
fits over a suction passage (see Figure 9B-30) in the
body of the cylinder assembly. Low pressure vapor
SUCTION PASSAGECOVER
TUBE9B-26
Figure 98-30 Suction Passage and Discharge Tubeflows from the suction port through the suction pas-
sage in the cylinder assembly, and into the suction
cavity of the front head.
9. Discharge Tube
- The discharge tube is used to
connect the discharge cavity in the front head with
the discharge cavity in the rear head. High pressure
vapor discharge is channeled via the tube to the dis-
charge cavity and port. A slightly modified discharge
tube is provided to be used as a service replacement
(see Figure
9B-31). The service replacement tube has
a reduced end and a built up shoulder to accomodate
an “0” ring and bushing. These added parts achieve
the necessary sealing of the high pressure vapor
within the compressor.
DISCHARGE
TUBE
oeR’NG\s~~~~~~G98.27
Figure 98.31 Service Replacement Discharge Tube
10. Pressure Relief Valve
- The purpose of the pres-
sure relief valve is to prevent the discharge pressure
from exceeding 440 psi. Opening of the pressure re-
lief valve will be accompanied by a loud popping
noise and the ejection of some refrigerant from the
valve. If the pressure relief valve is actuated due to
excessive pressures in the compressor, the cause of
the malfunction should be corrected immediately.
The pressure relief valve is located on the rear head
of the compressor.
11. Shell and Oil Drain Screw
- The shell of the
compressor contains a reservoir which furnishes a
continuous supply of oil to the moving parts of the
compressor. A
batTIe plate covers the reservoir and

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

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

9B-38 1973 OPEL SERVICE MANUAL
expand and return to the original gaseous state. To
accomplish this transformation it begins to boil.
The boiling action of the refrigerant demands heat.
To satisfy the demand for heat, the air passing over
the core gives up heat to the evaporator and is subse-
quently cooled.\
DIAGNOSIS
GENERAL INFORMATIONThe following is a brief description of the type of
sympton each refrigerant component will evidence if
a malfunction occurs:
Compressor malfunction will appear in one of four
ways: noise, seizure, leakage, or low discharge pres-
sure.Resonant compressor noises are not cause for alarm;
however, irregular noise or rattles may indicate
broken parts or excessive clearances due to wear. To
check seizure, de-energize the magnetic clutch and
check to see if drive plate can be rotated. If rotation
is impossible, compressor is seized. Low discharge
pressure may be due to a faulty internal seal of the
compressor, or a restriction in the compressor.
Low discharge pressure may also be due to an insuffi-
cient refrigerant charge or a restriction elsewhere in
the system. These possibilities should be checked
prior to servicing the compressor. If the compressor
is inoperative; but, is not seized, check to see if cur-
rent is being supplied to the magnetic clutch coil
terminals.
CondenserA condenser may malfunction in two ways: it may
leak, or it may be restricted. A condenser restriction
will result in excessive compressor discharge pres-
sure. If a partial restriction is present, sometimes ice
or frost will form immediately after the restriction as
the refrigerant expands after pas?ing through the re-
striction. If air flow through the condenser or radia-
tor is blocked, high discharge pressures will result.
During normal condenser operation, the outlet pipe
will be slightly cooler than the inlet pipe.
Receiver-DehydratorA receiver-dehydrator may fail due to a restriction
inside body of unit. A restriction at the inlet to the
receiver-dehydrator will cause high head pressures.
Outlet tube restrictions will be indicated by low headpressures. Outlet tube restrictions will be indicated
by
low head pressures and little or no cooling. An
excessively cold receiver-dehydrator outlet may be
indicative of a restriction.
Expansion ValveExpansion valve failures usually will be indicated by
low suction and discharge pressures, and insuff%ient
evaporator cooling. The failure is generally due to
malfunction of the power element and subsequent
closing of the valve. A less common cause of the
above symptom is a clogged inlet screen.
EvaporatorWhen the evaporator malfunctions, the trouble will
show up as inadequate supply of cool air. A partially
plugged core due to dirt or a faulty blower will gener-
ally be the cause.
Refrigerant Line Restrictions
Rest~rictions in the refrigerant lines will be indicated
as follows:
I. Suction Line - A restricted suction line will cause
low suction pressure at the compressor, low dis-
charge pressure and little or no cooling.
2. Discharge Line -A restriction in the discharge line
generally will cause the pressure relief valve to open.
3. Liquid Line
- A liquid line restriction will be evi-
denced by low discharge and suction pressure, and
insufficient cooling.
Use of Receiver-Dehydrator Sight Glass for
DiagnosisAt temperatures higher than 70 degrees F, the sight
glass may indicate whether the refrigerant charge is
sufficient. A shortage of liquid refrigerant is in-
dicated after about
five minutes of compressor oper-
ation by the appearance of slow-moving bubbles
(vapor) or a broken column of refrigerant under the
glass. Continuous bubbles may appear in a properly
charged system on a cool day. This is a normal situa-
tion. If the sight, glass is generally clear and perform-
ance is satisfactory, occasional bubbles do not
indicate refrigerant shortage.
If the sight glass consistently shows foaming or a
broken liquid column, it should be observed after
partially blocking the air to the condenser. If under
this condition the sight glass clears and the perform-
ance is otherwise satisfactory, the charge shall be
considered adequate.

REFRIGERANT COMPONENTS ALL MODELS96-39
In all instances where the indications of refrigerant
shortage continues, additional refrigerant should be
added in
l/4 lb. increments until the sight glass is
clear.
An additional charge of l/4 lb. should be ad-
ded as a reserve. In no case should the system be
overcharged.
LEAK TESTING SYSTEM
The following two methods are recommended when attempting to locate refrigerant leaks in the system.
Loss of
regrigerant is always indicative of a leak since
refrigerant is not consumed and does not wear out.
1. Open Flame Method
- This method utilizes a gas
operated torch type leak detector (J-6084). Use of
this method is recommended when checking for
leaks in confined areas. To perform test, light torch
and adjust to obtain a pale blue flame, approximately
3/8 inch in height, in burner.
Explore for leaks by moving end of search tube
around suspected area. Check bottom of connections
since Refrigerant-12 is heavier than air and will be more apparent at underside of fittings. The flame
color will turn yellow-green when a small leak is
detected. Large leaks will turn the flame blue or
purple.
WARNING:
Do not breathe fumes resdting from
burning of
refrigerant gas. These fumes az ex-
tremeiy poisonous.
2. Liquid Leak Detectors - This method utilizes a
solution which will bubble (soap solution) to signify
a gas leak. Use of this method of checking is recom-
mended for locating small leaks.
FUNCTIONAL TESTING SYSTEM
Functional testing is a measurement of the air condi-
tioner system performance to determine if discharge
air temperature, pressure in suction line, and pres-
sure in discharge line are within specific limitations.
To perform Functional test proceed as follows:
1. Remove protective caps from the compressor
adapter fittings located on compressor.
SCHRADER
ADAPTER J-5420
1II rDISCHARGE LINE
COMPRESSOR
VALVE
LOW PRESSURE
\ GAUGE\
HIGHGLR;B;URE
MANIFOLD AND
-GAUGE SET
J-5725-01
r
GAUGE LINES
(5) J-5418
9B-31
Figure 9B-40 Functional Test Set-Up

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.

REFRIGERANT COMPONENTS ALL MODELS9s. 41
BIower Operating Normal Check for the following:Restriction or leakage in air ducts, A/C outlets not
opening.2. Do not carry cylinder in passenger compartment
of car.3. Do not subject cylinder to high temperatures.
MAINTENANCE AND ADJUSTMENTS4. Do not weld or steam clean on or near cylinder.
5. Do not fill cylinder completely.
GENERAL SERVICE INFORMATION AND SAFETY
PRECAUTIONS6. Do not discharge vapor into area where flame is
exposed or directly into engine air intake.
General InformationAll subassemblies are shipped sealed and dehy-
drated. They are to remain sealed until just prior to
making connections, and should be at room tempera-
ture before uncapping. This prevents condensation of
moisture from air that enters the system.
All precautions should be taken to prevent damage
to fittings or connections. Even minute damage to a
connection could cause it to leak. Any fittings with
grease or dirt on them should be wiped clean with a
cloth dipped in alcohol.
Do not clean fitting or hoses with solvents because
they are contaminants. If dirt, grease or moisture
gets inside the pipes or hoses and cannot be removed,the pipe or hose is to be replaced. Use a small amount
of clean refrigeration oil on all tube and hose con-
necting joints, and lubricate the
“0” ring gasket with
this oil before assembling the joint. The oil will help
in effectitig a leak-proofjoint and assist the
“0” ring
to slip into the proper location without being cut or
damaged. Always use new
“0” rings.
When tightening joints, use a second wrench to hold
the stationary part of the connection to prevent
twisting and to prevent hose kinking. Kinked hoses
are apt to transmit noise and vibration. Tighten all
connections in accordance with recommended
torques (see Division VI, Specifications).7. Do not expose eyes to liquid
- WEAR SAFETY
GOGGLES whenever discharging, charging or leak
testing system.
CHARGING AND DISCHARGING SYSTEMRemoval of any part in the refrigerant circuit will
require discharging of the entire system.
Discharging the System1. Remove caps from gauge fittings on the compres-
sor adapter fitting on the compressor.
2. With both valves on manifold gauge set (J-5725-
04) closed (clockwise), attach manifold to the com-
pressor adapter fitting on the compressor, using
J-5420 valve adapter at suction gauge fitting and
J-9459 valve adapter at discharge gauge fitting. See
Figure
9B-41.3. Fully open high pressure valve on manifold gauge
set to allow escape of refrigerant from system
through the manifold gauge set and out the center
fitting and hose. (Place end of hose in clean container
to collect oil loss due to rapid discharge of system).
4. When hissing ceases, indicating all refrigerant
has escaped, close high pressure valve on manifold
gauge set by turning valve clockwise.
Do not connect receiver-dehydrator assembly until
all other connections have been made. This is neces-
sary to itisure maximum moisture removal from sys-
tem.It is important that air conditioning hoses do not rest
on or contact body sheet metal except where neces-
sary. Because of the high frequency at which the
compressor operates, the passenger compartment is
susceptible to transfer of noise.
Evacuating the SystemWhen the refrigeration system is depressurized and
opened for service, some air will enter the lines, re-
gardless of how quickly openings are capped. In
or-der to remove this air and as much as possible of the
moisture it contains, the complete system must be
evacuated. Evacuating is merely the process of
removing all air from the system, thereby creating a
vacuum in the system.
Safety PiecautionsThe following safety precautions should always be
followed~,when servicing refrigerant charged compo-nents:Under no circumstances should alcohol be used in
the system in an attempt to remove moisture,
regard-less of the successful use of alcohol in other refrigera-
tion systems.
Preparations for Evacuating Complete System
1. Do not leave Refrigerant-12 cylinder uncapped.
1. Check the low pressure gauge for proper calibra-