GENERAL INFORMATION
ENGINE COOLING14-2
GENERAL INFORMATION
M1141000100371The cooling system is designed to keep every part of
the engine at appropriate temperature in whatever
condition the engine may be operated. The cooling
method is of the water-cooled, pressure forced
circulation type in which the water pump pressurizes
coolant and circulates it throughout the engine. If the
coolant temperature exceeds the prescribed temperature, the thermostat opens to circulate the
coolant through the radiator as well so that the heat
absorbed by the coolant may be radiated into the air.
The water pump is of the centrifugal type and is
driven by the alternator drive belt from the
crankshaft. The radiator is the corrugated fin, down
flow type.
SERVICE SPECIFICATIONS
M1141000300416
LUBRICANT
M1141000400338
ItemSpecification
Radiator Performance kJ/h 4G13 Standard vehicles 137,720
Vehicles with capacity up radiator
(option)161,288
4G18 Standard vehicles 161,288
Vehicles with capacity up radiator
(option)181,800
4G63 181,800
A/T oil cooler Performance kJ/h 5,651
Item Standard value Limit
High-pressure valve opening pressure of radiator cap kPa 93 − 123 Minimum 83
Range of coolant antifreeze concentration of radiator % 30 − 60 -
Thermostat Valve opening temperature of
thermostat °C4G1 88 ± 1.5 -
4G6 82 ± 1.5 -
Full-opening temperature of
thermostat °C4G1 100 -
4G6 95 -
Valve lift mm 8.5 or more -
Item Specified coolant Quantity L
Engine coolant (including
condense tank)DIAQUEEN SUPER LONG LIFE COOLANT
or an equivalent4G1 5.0
4G6 7.0
WAT ER P U M P
ENGINE COOLING14-29
WAT E R P U M P
REMOVAL AND INSTALLATION <4G1>M1141002700421
INSTALLATION SERVICE POINT
>>A<< WATER PUMP ASSEMBLY
INSTALLATION
1. Use a gasket scraper or wire brush to completely
eliminate all gasket material on the gasket
mounting surface.2. Apply a bead of the specified sealant.
Specified Sealant: MITSUBISHI GENUINE
PART No.MD970389 or equivalent
3. With the sealant still wet (within 15 minutes after
the sealant is applied), install the water pump
assembly. Do not apply the sealant in an area
more than the required.
Pre-removal and Post-installation Operation
•Engine Coolant Draining and Refilling (Refer to P.14-22).
•Valve Timing Belt Removal and Installation (Refer to
GROUP 11A P.11A-33).
AC303372
24 ± 3 N·m 23 ± 2 N·m
14 ± 1 N·m
1
2
Bolt specifications
Screw diameter × length mm 8 × 50
8 × 308 × 25
AB
2
2
Sealant: Mitsubishi Genuine Part
No. MD970389 or equivalent
Removal steps
1. Alternator adjusting brace
>>A<<2. Water pump assembly
WAT E R P U M P
ENGINE COOLING14-30
REMOVAL AND INSTALLATION <4G6>M1141002700432
INSTALLATION SERVICE POINT
>>A<< COOLING WATER LINE O-RING
INSTALLATIONFit the cooling water line O-ring to the groove in the
water pump inlet pipe. Then lubricate the cooling
water line O-ring and the inside of the water pump
assembly with water, and then insert the water pump
inlet pipe to the water pump assembly.
Pre-removal and Post-installation Operation
•Engine Coolant Draining and Refilling (Refer to P.14-22).
•Valve Timing Belt and Balancer Timing Belt Removal and
Installation (Refer to GROUP 11C P.11C-35).
AC301467
22 ± 4 N·m
23 ± 3 N·m
14 ± 1 N·m
12
3 4
N
N
Bolt specifications
Screw diameter × length mm
8 × 708 × 22
8 × 14
8 × 22 8 × 25
2
AB
Removal steps
1. Alternator adjusting brace
2. Water pump assembly3. Water pump gasket
>>A<<4. Cooling water line O-ringRemoval steps (Continued)
AC103005
Water pump assembly
Cooling water
line O-ring
Water pump inlet pipe
AF
CHARGING SYSTEM
ENGINE ELECTRICAL16-3
SERVICE SPECIFICATIONSM1161000300258
SPECIAL TOOLM1161000600163
ON-VEHICLE SERVICE
ALTERNATOR OUTPUT LINE VOLTAGE DROP TESTM1161000900346
This test determines whether the wiring from the
alternator "B" terminal to the battery (+) terminal
(including the fusible line) is in a good condition or
not.
1. Always be sure to check the following before the
test.
•Alternator installation•Drive belt tension
(Refer to GROUP 11A − On-vehicle Service
<4G1> P.11A-7 or GROUP 11C − On-vehicle
Service <4G6> P.11C-7.)
•Fusible link
•Abnormal noise from the alternator while the
engine is running Item Standard value Limit
Alternator output line voltage drop (at 30 A) V
−maximum 0.3
Regulated voltage ambient
temperature at voltage regulator V−20°C14.2 − 15.4
−
20°C 13.9 − 14.9
−
60°C 13.4 − 14.6
−
80°C 13.1 − 14.5
−
Output current
−70 % of normal output current
Tool Number Name Use
MB991519 Alternator test harness Checking the alternator
("S" terminal voltage)
AK203361AD
AlternatorAmmeter (clamp-type)
Voltmeter (digital-type)
"B" terminalBattery
CHARGING SYSTEM
ENGINE ELECTRICAL16-5
OUTPUT CURRENT TESTM1161001000368
This test determines whether the alternator output
current is normal.
1. Before the test, always be sure to check the
following.
•Alternator installation
•Battery (Refer to GROUP 54A − Battery −
On-vehicle Service P.54A-5).
NOTE: The battery should be slightly discharged.
The load needed by a fully-charged battery is
insufficient for an accurate test.
•Drive belt tension
(Refer to GROUP 11A − On-vehicle Service <4G1>
P.11A-7 or GROUP 11C − On-vehicle Service
<4G6> P.11C-7.)
•Fusible link
•Abnormal noise from the alternator while the
engine is running.
2. Turn the ignition switch to the "LOCK" (OFF)
position.
3. Disconnect the negative battery cable.CAUTION
Never use clips but tighten bolts and nuts to
connect the line. Otherwise loose connections
(e.g. using clips) will lead to a serious accident
because of high current.
4. Connect a clamp-type DC test ammeter with a
range of 0 − 120 A to the alternator "B" terminal
output wire.
NOTE: The way of disconnecting the alternator
output wire and of connecting the ammeter is
possibly not found the problem that the output
current is dropping due to the insufficient
connection between terminal "B" and the output
wire.
5. Connect a voltmeter with a range of 0 − 20 V
between the alternator "B" terminal and the earth
[Connect the (+) lead of the voltmeter to the "B"
terminal, and then connect the (-) lead of the
voltmeter to the earth].
6. Connect the negative battery cable.
AK203362
Alternator Ammeter
(clamp-type)
Voltmeter
Battery Inition switch
Engine-ECU
Engine-A/T-ECU
Load
B
FR
L
S
G +
AH
–
Charging indicator
Brake warning light
CHARGING SYSTEM
ENGINE ELECTRICAL16-7
REGULATED VOLTAGE TESTM1161001100354
This test determines whether the voltage regulator
correctly controlling the alternator output voltage.
1. Always be sure to check the following before the
test.
•Alternator installation
•Check that the battery installed in the vehicle is
fully charged.
(Refer to GROUP 54A − Battery − On-vehicle
Service − Charging P.54A-4).
•Drive belt tension
(Refer to GROUP 11A − On-vehicle Service <4G1>
P.11A-7 or GROUP 11C − On-vehicle Service
<4G6> P.11C-7.)
•Fusible link
•Abnormal noise from the alternator while the
engine is running
2. Turn the ignition switch to the "LOCK" (OFF)
position.
3. Disconnect the negative battery cable.
4. Use the special tool Alternator test harness
(MB991519) to connect a digital voltmeter
between the alternator "S" terminal and earth
[Connect the (+) lead of the voltmeter to the "S"
terminal, and then connect the (-) lead of the
voltmeter to a secure earth or to the battery (-)
terminal].
5. Connect a clamp-type DC test ammeter with a
range of 0 − 120 A to the alternator "B" terminal
output wire.NOTE: The way of disconnecting the alternator
output wire and of connecting the ammeter is
possibly not found the problem that the output
current is dropping due to the insufficient
connection between terminal "B" and the output
wire.
6. Reconnect the negative battery cable.
7. Connect a tachometer or the MUT-II/III (Refer to
GROUP 11A − On-vehicle Service − Idle speed
check <4G1> P.11A-11 or GROUP 11C −
On-vehicle Service − Idle speed check <4G6>
P.11C-11).
8. Turn the ignition switch to the "ON" position and
check that the reading on the voltmeter is equal to
the battery voltage.
NOTE: If the voltage is 0 V, the cause is probably
an open circuit in the wire or fusible link between
the alternator "S" terminal and the battery (+)
terminal.
9. Turn all lamps and accessories off.
10.Start the engine.
11.Increase the engine speed to 2,500 r/min.
12.Read the value displayed on the voltmeter when
the alternator output current alternator becomes
10 A or less.
13.If the voltage reading conforms to the value in the
voltage regulation, then the voltage regulator is
operating normally.
AK300727AB
BatteryIgnition switch
Engine-ECU
Engine-A/T-ECU Ammeter (clamp-type)Load
Black MB991519
Voltmeter (digital-type) Red
YellowBlueAlternator B
FR
L
S
G
CHARGING SYSTEM
ENGINE ELECTRICAL16-12
ALTERNATOR ASSEMBLY
REMOVAL AND INSTALLATION <4G1>M1161001400548
REMOVAL SERVICE POINT
<> ALTERNATOR ASSEMBLY
REMOVAL
Remove the alternator assembly from above the
vehicle.
Pre-removal Operation
•Under Cover Removal
•Drive Belt Removal (Refer to GROUP 11A - Crankshaft
Pulley P.11A-16).Post-installation Operation
•Drive Belt Installation (Refer to GROUP 11A - Crankshaft
Pulley P.11A-16).
•Drive Belt Tension Adjustment (Refer to GROUP 11A -
On-vehicle Service P.11A-7).
•Under Cover Installation
AC303729
1
2
4
3
44 ± 10 N·m
23 ± 2 N·m
24 ± 3 N·m12 ± 2 N·m
AB
Removal steps
1. Power steering pressure hose
clamp
2. Alternator connector and terminal3. Alternator adjusting brace
<>4. Alternator assemblyRemoval steps (Continued)
ON-VEHICLE SERVICE
HEATER, AIR CONDITIONER AND VENTILATION55-74
REFRIGERANT LEAK REPAIR
PROCEDURE
M1552001500277
LOST CHARGE
If the system has lost all charge due to a leak:
1. Evacuate the system (Refer to P.55-72).
2. Charge the system with approximately 480 − 520
g of refrigerant.
3. Check for leaks.
4. Discharge the system.
5. Repair leaks.
CAUTION
Replacement filter-drier units must be sealed
while in storage. 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 assembly to
avoid keeping the system open any longer than
necessary.
6. Replace receiver drier.
7. Evacuate and charge system.
LOW CHARGE
If the system has not lost all of its refrigerant charge;
locate and repair all leaks. If it is necessary to
increase the system pressure to find the leak
(because of an especially low charge) add
refrigerant. If it is possible to repair the leak without
discharging the refrigerant system, use the
procedure for correcting low refrigerant level.
HANDLING TUBING AND FITTINGS
Kinks in the refrigerant tubing or sharp bends in the
refrigerant hose lines will greatly reduce the capacity
of the entire system. High pressures are produced in
the system when it is operating. Extreme care must
be exercised to make sure that all connections are
pressure tight. Dirt and moisture can enter the
system when it is opened for repair or replacement of
lines or components. The following precautions must
be observed. The system must be completely
discharged before opening any fitting of connection
in the refrigeration system. Open fittings with caution
even after the system has been discharged. If any
pressure is noticed as a fitting is loosened, allow
trapped pressure to bleed off very slowly.
Never attempt to rebend formed lines to fit. Use the
correct line for the installation you are servicing. A
good rule for the flexible hose lines is keep the radius
of all bends at least 10 times the diameter of the
hose.Sharper bends will reduce the flow of refrigerant. The
flexible hose lines should be routed so that they are
at least 80 mm from the exhaust manifold. It is good
practice to inspect all flexible hose lines at least once
a year to make sure they are in good condition and
properly routed.
On standard plumbing fittings with O-rings, these
O-rings are not reusable.
COMPRESSOR NOISE CHECKM1552008700272
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 A/C 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 or alternator).
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
1. Select a quiet area for testing. Duplicate
conditions as much as possible. Switch the
compressor on and off several times to clearly
identify compressor noise. To duplicate high
ambient conditions (high head pressure), restrict
air flow through the condenser. Install a manifold
gauge set to make sure discharge pressure
doesn't exceed 2,070 kPa.
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 (Refer to P.55-69).
5. Recheck compressor noise as in Step 1.
6. If noise still exists, loosen compressor mounting
bolts and retighten. Repeat Step 1.
7. If noise continues, replace compressor and repeat
Step 1.