1987 MITSUBISHI MONTERO clutch

AIR-CONDITIONING-Service Adiustment Procedures 24-31
FREEZE UP CONTROL
Evaporator freeze up is controlled by a thermistor attached to the
evaporator fins. The control is an electronic type and consists of
two parts_(thermo relay and thermistor.) It is connected to the
magnetic clutch of the compressor in series. When the tempera-
ture of the evaporator drops below 3°C (37.4”F), the compressor is
turned OFF.
To Test the Thermistor
(1) Jump the wire lead (LB to GB) of the connector portion.
(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 clutch engaging.
(4) If the clutch does not engage, the low pressure switch,
water temperature switch wiring or fuse may be faulty.
(5) If the clutch operates, replace the thermostat.
WATER TEMPERATURE SWITCH
The water temperature switch is located on the thermostat hous-
ing. The water temperature switch is connected to the clutch
in series. When the coolant temperature in the radiator
reaches above 113°C (235”F), it turns the compressor OFF.
This is to prevent engine overheating.
When the water temperature switch is activated and the clutch is
OFF, check the surface of the condenser and radiator, the belt
tension, and the coolant volume in the radiator, and return to the
normal condition.
To Test the Water Temperature Switch
(1) Remove wire from water temperature switch and jump lead
wires.
(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 clutch engaging.
(4) If the clutch does not-engage, the fin thermistor, low pressure
switch, wiring or fuse may be faulty.
(5) If clutch engages, replace the switch.
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24-32 AIR-CONDITIONING-Service Adjustment Procedures
i--
9 >
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2ouo319
- 2OW627 I
Suction gauge Discharge w-w
/ I
Suction
ww Discharge
w-w
2OUO306
Suction
w-w Discharge
gauge
2OUO307
AIR CONDITIONER SWITCH
To jest the Air Conditioner Switch
(1) Disconnect the harness connector for the air conditioner
switch.
(2) Jump the lead wires as shown.
(3) Turn the blower switch ON.
(4) Momentarily turn the ignition switch on (do not crank the en-
gine), listen for the clutch engaging.
(5) If the clutch does not engage, fin thermostat, water
temperature switch, wiring or fuse may be faulty.
(6) If clutch engages, replace the air conditioner switch.
MAGNETIC CLUTCH
(1) Disconnect the wiring to the magnetic clutch.
(2) Connect battery (+) voltage directly to the wiring for the mag-
netic clutch.
(3) If the magnetic clutch is normal, there will be a “click”. If the
pulley and armature do not make contact (“click”), there is a
malfunction.
COMPRESSOR
(1) Install the manifold gauge set, and run the air conditioner.
(2) If a pressure of approx.490 kPa (71 psi) is indicated on the
suction gauge side and a pressure of approx.883 kPa (128 psi)
is indicated on the discharge gauge side, the compressor has
abnormal compression.
Replace the compressor.
(3) If a pressure of 294 to 392 kPa (43 to 59 psi) is indicated on the
suction gauge side and a pressure of approx.1961 kPa (284
psi) is indicated on the discharge gauge side, it is suspected
that air is present in the air conditioning system.
Discharge the system, evacuate and recharge with specified
amount of refrigerant.
(4) During operation of the air conditioner, cold air may stop flow-
ing after the elapse of time and this state is maintained before
cold air flows out again. If cold air stops flowing out with
negative pressure indicated on the suction gauge side and a
pressure of 588 to 980 kPa (85 to 142 psi) indicated on the
discharge gauge side, it is suspected that water is present in
the air conditioning system.
Discharge the system. Replace receiver drier. Evacuate and
check for leaks, and recharge with specified amount of refrig-
erant.
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24-34 AIR-CONDITIONING-Service Adiustment Procedures
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Dry bulb therr&neter
2OW825
PEAFORMANCE TEST
TESI N24FWAB NOTE
Air temperature in test room must be 21°C (70°F) minimum for this
test.
(1) Connect a tachometer and manifold gauge set.
(2) Set air conditioner controls to Max air conditioner, tempera-
ture lever on full cool, and blower on high.
(3) Turn engine on 1000 rpm with air conditioner clutch engaged.
(4) Engine should be warmed up with doors, windows, and hood
open.
(5) Insert a thermometer in the left center air conditioner outlet
and operate the engine for 5 minutes.
(6) Note the discharge air temperature.
NOTE
If the clutch cycles, take the reading before the clutch disen-
gages.
Performance Temperature Chart Garage ambient
temperature
21 “C 26.5 “C 32 “C 37.5 “C 40.6 “C (70 “F) (80 “F) (90 “F) (100 “F) (I 05 “F)
Discharge air
temperature
Compressor
discharge pressure
Evaporator suction
pressure
1.7-4.4 “C 1.7-5.0 “C 1.7-5.6 “C 1.7-6.1 “C 1.7-6.7 “C (35-40 “F) (35-41 “F) (35-42 “F) (35-43 “F) (35-44 “F)
928- 1,322 kPa 1.069-1.547 kPa 1,209-1,772 kPa 1,336-1,969 kPa 1,406-2,109 kPa
(132-188 psi) (152-220 psi) (172-252 psi) (190-280 psi) (200-300 psi)
127-148 kPa
131-162 kPa 134-176 kPa 135- 188 kPa 136-194 kPa
(18-21 psi) (18.6-23 psi) (19-25 psi) (19.2-26.8 psi) (19.4-27.6 psi)
REFRIGERANT LEAK REPAIR PROCEDURE N24FnAB
LOST CHARGE If the system has lost all charge due to a leak:
(1) Evacuate the system. (See the procedure).
(2) Charge the system with approximately one pound of refriger-
ant.
(3) Check for leaks.
(4) Discharge the system.
(5) Repair leaks.
(6) Replace receiver drier.
Caution
Refrigerant
leak tester
Replacement filter-drier units must be sealed while in stor-
age. The drier used in these units will saturate water quickly
upon exposure to the atmosphere. When installing a drier,
have all tools and supplies ready for quick reassembly to
avoid keeping the system open any longer than necessary. (7) Evacuate and charge the system.
LOW CHARGE If the system has not lost all of its refrigerant charge; locate and
tester repair all leaks. If it is necessary to increase the system pressure
up to find the leak (because of an especially low charge) add refrig-
erant. If it is possible to repair the leak without discharging the
refrigerant system, use the procedure for correcting low refriger-
2OUO316 ant level.
1 STB Revision

AIR-CONDITIONING-Service Adiustment Procedures 24-35
CORRECTING LOW REFRIGERANT LEVEL Suction
Discharge gauge
gauge
I \- a/
gauge valve
II II Discharge gauge
Ho water
52°C i 125°F)
2OUO325
Since the refrigeration system is completely sealed, refrigerant level will not be low unless there is a leak in the
system.
Before adding refrigerant when the cause of low level is not known, the system should be tested for leaks.
Assuming that leaks have been corrected without discharging the system, proceed with partial charge.
Install and connect manifold gauge set.
(I) Close both gauge set manifold valves.
(2) Connect the suction gauge test hose to the suction port of the compressor. Connect the discharge gauge test
hose to the discharge port.
(3) Connect one end of long test hose to center manifold outlet, other end to refrigerant dispensing manifold.
(4) Close two dispensing manifold valves and open remaining dispensing manifold valve. Remove protective cap
from opened valve.
(5) Screw a can of R-12 to the opened manifold valve. Be sure gasket is in place and in good condition. Tighten
refrigerant can and manifold locking nut to insure a good seal. Do not overtighten. 8 to 11 Nm (6 to 8 ft.lbs.) is
sufficient if gasket is in good condition.
(6) Turn manifold valve (above the refrigerant can) completely clockwise to puncture the can. This closes the valve
and seals the refrigerant in the can. Caution
Never heat small cans of refrigerant over 52°C (125’F) as they may explode.
(7) Place the refrigerant in a large pan of water heated to 52°C (125°F). Place pan of water containing the refrigerant
can on an accurate scale so the amount of refrigerant added can be weighed. Open the refrigerant manifold
valve. (8) Purge all air from test hoses.
Air in the system will be trapped in the condenser causing abnormally high
discharge pressures and interfering with condensing of the refrigerant.
(9) Slightly loosen both test hoses at the gauge set manifold. Tighten the hoses as soon as the air is purged.
(10)Slightly loosen charging hose connection at gauge set manifold. This will purge air from the charging hose.
Tighten connection as soon as air is purged.
(1l)With vehicle windows open and hood up, operate engine at 1,500 rpm and jump the switch terminals located
on so the clutch will remain engaged.
(12)Place air conditioner control on air conditioner and place the blower switch on high.
(13)lf necessary, block the condenser to maintain a discharge pressure of 1,422 to 1,520 kPa (206 to 220 psi.).
System must be charged through the evaporator suction service ports as follows:
(a) Slowly open the suction service gauge valve.
Meter flow of refrigerant by adjusting the suction service
gauge valve so that pressure registered at the suction service gauge does not exceed 345 kPa (50 psi). Keep refrigerant container upright.
(b) Add refrigerant gas until there is no foam visible at the sight glass.
(c) Close the suction gauge valve. Caution
Too much refrigerant in the system can cause abnormally high discharge pressures. Care must be
used so that the exact recommended amount of refrigerant is added after foam clears in the sight
glass.
(d) Close dispensing manifold valve. Remove test hoses and adapters from the service ports of compressor,
install protective caps at service ports and reconnect wiring. / STB Revision

24-38 AIR-CONDITIONING-Service Adjustment Procedures
(4) Purge the air from the charging line by loosening the charging
hose at the gauge set manifold and turning one of the refrig-
erant valves counterclockwise to release refrigerant. When
the refrigerant gas starts escaping from the loose connection,
re-tighten the hoses.
Caution
Never heat small refrigerant cans over 52°C (125°F) as they
mad explode.
(5) qully open all refrigerant manifold valves being used and place
the cans of refrigerant into a pan containing 52°C (125°F) water
will warm the charging can and aid in the transfer of the charge
into the system. Place the water pan and refrigerant cans on
a scale and note the weight.
(6) Jump the low pressure switch terminals located on the re-
ceiver drier so the clutch will remain engaged.
(7) Start the engine and move the controls to air conditioner
switch on and low blower position.
The low pressure switch will prevent the clutch from engaging
until refrigerant is added to the system. If the clutch does
engage, replace the switch before proceeding any further.
(8) Charge through the suction side of the system by slowly open-
ing the suction manifold valve. Adjust the valve as necessary
so charging pressure does not exceed 345 kPa (50 psi).
Maintain the temperature of the water in the pan by adding
warm water as necessary. Note the weight of water
added, to ensure accuracy when determining amount of
refrigerant added to system.
(9) Adjust the engine speed to a fast idle of approximately 1500
rpm.
(IO) When specified refried refrigerant charge 730 (1.6 Ibs.) has
entered the system, close the gauge set manifold valves,
refrigerant manifold valves, and reconnect wiring. Each
can contains 397 g (14 oz.) of R-12. Use 2 l/2 cans.
1 STB Revision
-1

AIR-CONDITIONING -Service Adjustment Procedures 24-41
COMPRESSOR NOISE NWLM
When investigating an air conditioning related noise, you must first know the conditions when the noise occurs.
These conditions are: weather, vehicle speed, in gear or neutral, engine temperature or any other special
conditions.
Noises that develop during air- conditioning operation can often be misleading. For example: what sounds like a
failed front bearing or connecting rod, may be caused by loose bolts, nuts, mounting brackets, or a loose clutch
assembly. Verify accessory drive belt tension (power
steering, alternator or air pump). Improper accessory drive belt
tension can cause a misleading noise when the compressor is engaged and little or no noise when the compressor
is disengaged.
Drive belts are speed sensitive. That is, at different engine speeds, and depending upon belt tension, belts can
develop unusual noises that are often mistaken for mechanical problems within the compressor.
Adjustment Procedures
(1) Select a quiet area for testing. Duplicate conditions as much as possible. Switch compressor on and off several
times to clearly identify compressor noise.
To duplicate high ambient conditions (high head pressure), restrict air-flow through
condenser. Install
manifold gauge set to make sure discharge pressure does not exceed 2,070 kPa (300 psi).
(2) Tighten all compressor mounting bolts, clutch mounting bolt, and compressor drive belt. Check to assure clutch
coil is tight (no rotation or wobble).
(3) Check refrigerant hoses for rubbing or interference that can cause unusual noises.
(4) Check refrigerant charge (See “Charging the System”).
(5) Recheck compressor noise as in Step 1.
(6) If noise still exists, loosen compressor mounting bolts and retorque. Repeat Step 1.
(7) If noise continues, replace compressor and repeat Step 1.
1 STB Revision

AIR-CONDITIONING - Receiver drier, Condenser, Compressor Clutch Assembly 24-45
RECEIVER DRIER, CONDESER, COMPRESSOR CLUTCH ASSEMBLY
REMOVAL AND INSTALLATION N24TA--
Pre-removal Operation l Discharge the Refrigerant. (Refer to
P.24-36)
l Remove the Radiator Grille. (Refer
to GROUP 23 BODY-Grille, Garnish,
Moulding)
l Disconnect the Liquid Pipes and
Hoses.
Post-installation Operation
l Install the Radiator Grille. (Refer to
GROUP 23 BODY-Grille, Garnish,
Moulding)
l Charge the Refrigerant. (Refer to
P.24.37)
l Adjustment of the Tension of the
Air Conditioner Drive Belt. (Refer to
P.24-40)
2OW832 Receiver drier removal steps
Compressor clutch assembly removal steps
1. Reveiver drier mounting bolt
8. Drive belt
2. Receiver drier
9. Compressor clutch assembly mounting
Condenser removal steps
3. Blower motor connector
4. Blower motor mounting bolt
5. Blower motor
6. Condenser mounting bolt
7. Condenser bolt
10. Compressor clutch assembly
NOTE
Reverse the removal procedures to reinstall.
SERVICE POINTS OF REMOVAL N24TBAB 1 STB Revision Caution
If the hoses or pipes are disconnected,cap the hoses or pipes
with a blank plug to prevent entry of dust, dirt, and water.

24-46
COMPRESSOR
AIR-CONDITIONING - Compressor
DISASSEMBLY AND REASSEMBLY N24TE-
15-h Nm
11-13 ftlbs 16
a 0
I
26-26 Nm
16-20 ftlbs. Magnetic clutch disassembly steps
1. Nut
~~ Adjustment of clutch clearance
2. Clutch hub
3. Shims
4.
Snap ring
4* 5. Rotor assembly
6.
Snap ring
7.
Ground terminal
l + 8. Clutch coil
l5Dl
2QY947 Compressor front housing and service valve disas-
sembly steps
9. Oil drain guide
10.
Woodruff key
Il. Through bolt
** Refilling of compressor oil
12. Front housing
o+
13. Shaft seal
04 14.
Shaft plate
15.
Gasket
16. O-ring
NOTE
(1) Reverse the disassembly procedures to reassemble.
(2) +e : Refer to “Service Points of Disassembly”.
(3) e+ : Refer to “Service Points of Reassembly”.
(4)
q : Non-reusable parts 1 STB Revision