1987 MITSUBISHI MONTERO clutch

24-1
AIR-CO IONING
CONTENTS
AIR-CONDITIONING
AIR CONDITIONER SWITCH ......................... 42
CIRCUIT DIAGRAM ...................................... . . 26
COMPRESSOR ............................................... 46
EVAPORATOR ............................................ . ... 43
GENERAL INFORMATION .............. . ....... . . . .... 19
RECEIVER DRIER, CONDENSER,
COMPRESSOR CLUTCH ASSEMBLY .......... 45
SAFETY PRECAUTIONS ................................ 28
SERVICE ADJUSTMENT PROCEDURES ...... 29
Compressor Drive Belt Adjustment ...........
40
Compressor Noise ..................................... 41
Handling Tubing and Fittings ..................... 39
Manifold Gauge Set Installation ................ 29
Performance Test ...................................... 34
Refrigerant Leak Repair Procedure ........... 34
Test Procedures ......................................... 29
Testing System for Leaks .......................... 33
SPECIAL TOOLS ............................................ 22
SPECIFICATIONS ...... . .
.. . ................................ 21
General Specifications ...............................
21
Service Specifications ................................
21
Torque Specifications ................................
21
TROUBLESHOOTING .................................... 22 Air is Emitted but Is Not Cool
Cool Air Flow Is Intermittent
Insufficient Air Flow
Insufficient Cooling
HEATERS
BLOWER ASSEMBLY . . . . . . . . . . . . . . . . . . ..a............... 14
CIRCUIT DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
HEATER CONTROL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
HEATER UNIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
SERVICE ADJUSTMENT PROCEDURES . . . . . . 5
Temperature Control System
Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Water Valve Replacement . . . . . . . . . . . . . . . . . . . . . . . 8
TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Blower Motor Inoperative
Blower Motor Operates on High
Speed Only
Improper Heat
No Ventilation Even When Mode
Selection Lever Is Operated
VENTILATORS . . . . . . . . . . . . . . . . . . . . . . . . . . . ..a..... . . . . . . . . . . . .
16

24-20 AIR-CONDITION!NG-General Information
I
AIR-CONDITIONING SYSTEM COMPO
N24BBBB
Condenser MDuct, joint (Blower side)
oint (Heater unit
Condenser
2OWB31
Suction Pipe Receiver bracket side)
COMPRESSOR - The prime purpose of the compressor is to compress the low pressure refrigerant vapor
from the evaporator into a high pressure, high temperature vapor. The 6 cylinder 6P148 compressor is used.
MAGNETIC CLUTCH is mounted on the compressor providing a convenient way to drive and disengage
compressor in accordance to the cooling needs. CONDENSER is located in front of the radiator. Its function
is to cool the hot, high pressure refrigerant gas causing it to condense into high pressure liquid refrigerant.
RECEIVER DRIER is used to remove any traces of moisture from the refrigerant system. This component
incorporates the sight glass and fusible plug. SIGHT GLASS at the top of the receiver drier is provided as a
diagnostic tool to observe refrigerant flow and observe refrigerant level. THE FUSIBLE PLUG is located on
the receiver drier. Its function is to prevent damage to the air conditioning system in the event that
excessive pressure develops due to condenser air flow being restricted by, for example, leaves, newspaper,
an overcharge of refrigerant, or air in the system. LOW PRESSURE SWITCH prevents damage to the
compressor in case of system loss of refrigerant charge. EXPANSION VALVE - The expansion valve is used
for all applications. Its function is to meter refrigerant into the evaporator in accordance with cooling
requirements. EVAPORATOR COIL is located in the unit and its function is to cool and dehumidify the air
before it enters the vehicle. FREEZE UP CONTROL FIN THERMOSTAT SENSOR is installed at the heater
side of evaporator. The main function of a freeze control is to keep condensate water on the face of the
evaporator coil from freezing and restricting air flow. WATER TEMPERATURE SWITCH - When the
temperature of the radiator coolant became high, this switch functions to stop the compressor and prevent
engine overheating. SERVICE VALVE at the compressor and the discharge line. The valves are used to test
and service the refrigerant system. REFRIGERANT R-12 is used maximum amount 907 g (32 oz.) R-12.
COMPRESSOR OIL is used DENS0 oil 6 maximum amount 110 cc (3.7 U.S.fl.oz., 3.9 Imp.fl.oz.).
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AIR-CONDITIONING -Specifications
SPECIFICATIONS
GENERAL SPECIFICATIONS
24-2 1
N24CA-
Items Specifications
Compressor
Model
6P148lnclined-plate type
No. of cylinders and displacement
6 cylinders 6,148 (208,216)
cc. (U.S.fl. oz., Imp.fl.02.)
Refrigeration unit lubricant
cc. (U.S.fl. oz., Imp.fl.oz.) DENS0 oil 6 110 (3.7,3.9)
Protective equipment
OFF: 1 .O (22) ON:4.5 (39)
Cycling clutch switch
“C(“F)
OFF:210 (30) ON:230 (33)
Low pressure switch
kPa (psi)
OFF: 113 (235) ON:106(222)
Water temperature switch
“C (“F)
Air temperature thermostat
Freezor prevention
“C (“F) OFF:3 (37.4) ON:5 (41)
Burn out temperature 106 (222)
Fusible plug “C (“F)
R-l 2 600-900 (1.3-2.0)
Refrigerant and quantity
g (Ibs.1
SERVICE SPECIFICATIONS N24CE-
Items Specifications
Standard value
Drive belt deflection mm (in.) 17.20 (.7-.8)
Pressure plate to rotor clearance mm (in.)
0.4-0.7 (.02-.03)
TORQUE SPECIFICATIONS N24CG Items Nm ftlbs.
Suction hose to cooling unit 30-35 22-25
Liquid pipe to cooling unit 12-15 9-l 1
Liquid pipe to receiver drier 12-15 9-l 1
Suction hose to suction hose 30-35 22-25
Liquid pipe to liquid pipe 12-15 9-l 1
Liquid pipe to condenser 20-25 15-18
Suction hose to compressor 30-35 22-25
Discharge hose to compressor 20-25 15-18
Discharge hose to liquid pipe 20-25 15-18
Compressor shaft nut 15-17 11-13
Through bolt 25-26 18-20
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24-22 AIR-CONDITIONING - Special TOOIS / Troubleshooting
SPECIAL TOOLS
Tool (Number and name)
MB990783-01
Steering/pinion gear
remover/installer Use
Installation of seal plate
TROUBLESHOOTING N24EBAE
Before replacing or repairing air conditioning compofents, first determine if the malfunction is; due to refrigerant
charge, air flow, or compressor related.
The following diagnostic charts have been developed as a “quick reference” aid in determining the cause of
malfunction. If these charts do not satisfactorily describe the problem, refer to appropriate section for detailed
explanation.
N24DA.-
After correcting the malfunction, check out the complete system to assure satisfactory performance.
MALFUNCTION CAUSES AND REMEDIES (Numbers indicate checking/inspection order.)
1 not cool 1 Air is
emitted
but is * 1. Magnetic clutch is
not switched ON
SEE NEXT PAGE 1 Replace
1
I
I I
-4 2.Check the fuse (IOA)
t-l Replace
I
I I
I ,
I
3,Check the air-conditioner
__) Replace
switch (P.24-32)
I
4.Check the low pressure
switch (P.24-30) - Replace
---L 5.Check the thermistor
- Replace
and therm0 relay (P.24-31)
- 6.Check the blower
switch (P.24-10) - Replace
-i 7.Check the blower relay
M Replace
(P.24-15)
8.Check the magnetic clutch
(P.24-32) Replace
I
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AIR-CONDITIONING-Service Adjustment Procedures
SERVICE ADJUSTMENT PROCQDURES 24-29 N24FDAD
MANIFOLD GAUGE SET INSTALLATUON Discharge
W gauge
Suction
gauge
Suction
gauge
valve Manifold Gauge Valves should be closed
when connecting the manifold gauge set to the service port of the
compressor and the discharge hose. The suction gauge valve at the left is opened to provide a passage between
the suction gauge and the center manifold outlet. The discharge gauge valve at the right is opened to provide a
passage between the discharge pressure gauge and the center manifold outlet.
Detailed instructions for proper use of the gauge set manifold are contained in the text covering each test and
service operation employing these gauges.
Suction Gauge; the left side of the manifold set is calibrated to register 0 to-100 kPa (0 to 30 in. of vacuum) and
0 to 1000 kPa (0 to 150 psi). This gauge is connected to the suction port of the compressor.
Discharge Gauge; the right of the manifold set is calibrated to register 0 to 2100 kPa (0 to 300 psi). For all
tests this gauge is connected to the discharge port of the system.
Center Manifold Outlet provides the necessary connection for a long service hose used when discharging the
system, using a vacuum pump to “pull a vacuum” before charging the system, and for connecting the supply of
refrigerant when charging the system
glass -
2OW724 N24FEAE The receiver drier assembly consists of; Drier reservoir, Refriger-
ant level sight glass and Fusible plug.
To Test the Receiver Drier (1) Operate the unit and check the piping temperature by
touching the receiver drier outlet and inlet.
(2) If there is a difference in the temperatures, the
received drier is restricted.
Replace the receiver drier.
SIGHT GLASS REFRlGERANT LEVEL TEST The sight glass is a refrigerant level indicator. To check the refrigerant level, clean the sight glass and start the
vehicle engine. Push the air conditioner button to operate the compressor, place the blower switch to high and
move the temperature lever to extreme left.
After operating for a few minutes in this manner, check the sight glass.
(1) If the sight glass is clear, the magnetic clutch is engaged, the compressor discharge line is warm and the
compressor inlet line is cool; the system has a full charge.
(2) If the sight glass is clear, the magnetic clutch is engaged and there is no significant temperature difference
between compressor inlet and discharge lines; the system has lost some refrigerant.
(3) If the sight glass is clear and the magnetic clutch is disengaged; the clutch is faulty or, the system is out of
refrigerant. Perform low pressure switch test to determine condition. Check low pressure switch and clutch coil
for electrical continuity.
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AIR-CONDITIONING - Circuit Diagram 24-27
Air conditioner relay
@,0.85-WB
El
Low pressure
switch
A-54 El
85-BW:0.85-BW ) To feed back carburetc
u control unit
A-25 [Refer to P.8-39.1
*20.85-BWr
*10.85-BWi& Vacuum solenoid
A-13 ++ valve
A-45
Condenser Condenser blower
blower motor motor relay
A
rl z-
BY
37W611 Magnetic
clutch
(compressor)
Remarks
(1) For information converning the ground points (exam-
ple.(l)m), refer to P.8-7.
(2) The symbols 0, 0, etc indicate that the wiring is
connected (using the same numerical symbol) to the
facing page (In other words, 0 on the right page is
connected to 0 on the left page.)
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AIR-CONDITIONING-Service Adjustment Procedures
SERVICE ADJUSTMENT PROCQDURES 24-29 N24FDAD
MANIFOLD GAUGE SET INSTALLATUON Discharge
W gauge
Suction
gauge
Suction
gauge
valve Manifold Gauge Valves should be closed
when connecting the manifold gauge set to the service port of the
compressor and the discharge hose. The suction gauge valve at the left is opened to provide a passage between
the suction gauge and the center manifold outlet. The discharge gauge valve at the right is opened to provide a
passage between the discharge pressure gauge and the center manifold outlet.
Detailed instructions for proper use of the gauge set manifold are contained in the text covering each test and
service operation employing these gauges.
Suction Gauge; the left side of the manifold set is calibrated to register 0 to-100 kPa (0 to 30 in. of vacuum) and
0 to 1000 kPa (0 to 150 psi). This gauge is connected to the suction port of the compressor.
Discharge Gauge; the right of the manifold set is calibrated to register 0 to 2100 kPa (0 to 300 psi). For all
tests this gauge is connected to the discharge port of the system.
Center Manifold Outlet provides the necessary connection for a long service hose used when discharging the
system, using a vacuum pump to “pull a vacuum” before charging the system, and for connecting the supply of
refrigerant when charging the system
glass -
2OW724 N24FEAE The receiver drier assembly consists of; Drier reservoir, Refriger-
ant level sight glass and Fusible plug.
To Test the Receiver Drier (1) Operate the unit and check the piping temperature by
touching the receiver drier outlet and inlet.
(2) If there is a difference in the temperatures, the
received drier is restricted.
Replace the receiver drier.
SIGHT GLASS REFRlGERANT LEVEL TEST The sight glass is a refrigerant level indicator. To check the refrigerant level, clean the sight glass and start the
vehicle engine. Push the air conditioner button to operate the compressor, place the blower switch to high and
move the temperature lever to extreme left.
After operating for a few minutes in this manner, check the sight glass.
(1) If the sight glass is clear, the magnetic clutch is engaged, the compressor discharge line is warm and the
compressor inlet line is cool; the system has a full charge.
(2) If the sight glass is clear, the magnetic clutch is engaged and there is no significant temperature difference
between compressor inlet and discharge lines; the system has lost some refrigerant.
(3) If the sight glass is clear and the magnetic clutch is disengaged; the clutch is faulty or, the system is out of
refrigerant. Perform low pressure switch test to determine condition. Check low pressure switch and clutch coil
for electrical continuity.
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24-30 AIR-CONDITIONING -Service Adjustunent Procedures
(4) If the sight glass shows foam or bubbles, the systpm could be low on charge. Occasional foam or bubbles are
normal when the ambient temperature is above 43”C(110”F) or below 21”C(7O”F).
Adjust the engine speed to 1,500 rpm. Block the airflow through the condenser to increase the compressor
discharge pressure to 1,422 to 1,520 kPa (20$ to 220 dsi). If sight glass still shows bubbles or foam, system charge
level is low.
The refrigerant system will not be low on charge unless there is a leak. Find and repair the leak. If the leak can be
repaired without discharging the system an oil level check is not necessary. Use the procedure for correcting low
refrigerant level found in the Refrigerant Sy$em Service Procedure Section.
FUSIBLE PLUG
When ambient temperature of the fusible plug reach& 105~221~F), the fusible plug melts and the refrigerant in
the system is released.
Once the fusible plug is operated, it cannot be used again.
SO, it is necessary to install new one and charge the refrigerant in the system.
Low pressure
switch , LOW PRESSURE SWITCH
The Low Pressure Switch, located on the liquid line, is wired in
series with the magnetic clutch. It cuts off the electrical power
supply to the clutch when refrigerant pressure drops below the
cont$ol point of the switch. Whenever the system is inactivated by
the low pressure switch due to refrigerant loss, the refrigerant oil
may have been lost. Therefore, to prevent damage to the com-
pressor due to operation without sufficient lubrication, the leak
must be repaired and the compressor oil level checked before final
charge of the system. The switch is a sealed, factory calibrated
unit. No attempt should be made to adjust or otherwise repair it.
If it is found to be faulty it must be replaced.
To Test the Low Pressure Switch (Engine Off)
(1) Jump the wire leads.
(2) Press the air conditioner switch and blower switch on.
(3) Momentarily turn the ignition switch on (do not crank the en-
gine), listen for the compressor clutch engaging.
(4) If the clutch does not engage, the fin thermostat, water tem-
perature switch or fuse may be faulty.
(5) If clutch engages, connect the manifold gauge set and
read pressure. At pressure of 210 kPa (30 psi) or above,
switch must actuate the clutch.
If the pressure is below 210 kPa (30 psi), the refrigerant
system is low in charge. For corrective action refer to
refrigerant leak repair procedure.
(6) Reconnect boot on switch and perform step number 3.
If the clutch does not engage, discharge the system, replace
the switch, and recharge the system.
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