14-1
GROUP 14
ENGINE COOLING
CONTENTS
GENERAL INFORMATION . . . . . . . .14-2
SERVICE SPECIFICATIONS . . . . . . .14-2
LUBRICANT . . . . . . . . . . . . . . . . . . . .14-3
SEALANTS . . . . . . . . . . . . . . . . . . . .14-3
SPECIAL TOOLS . . . . . . . . . . . . . . . .14-3
TROUBLESHOOTING . . . . . . . . . . . .14-5
INSPECTION CHART FOR TROUBLE
SYMPTOMS . . . . . . . . . . . . . . . . . . . . . . . . 14-5
INSPECTION PROCEDURE FOR
TROUBLE SYMPTOMS . . . . . . . . . . . . . . . 14-6
ON-VEHICLE SERVICE . . . . . . . . . . .14-21
ENGINE COOLANT LEAK CHECK . . . . . . 14-21
RADIATOR CAP VALVE OPENING
PRESSURE CHECK . . . . . . . . . . . . . . . . . . 14-21
ENGINE COOLANT REPLACEMENT . . . . 14-21
CONCENTRATION MEASUREMENT . . . . 14-22
COOLING FAN MOTOR DRIVE
CONTROL UNIT CHECK . . . . . . . . . . . . . . 14-22
FAN CONTROL RELAY CONTINUITY
CHECK . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-23
COOLING FAN MOTOR CHECK . . . . . . . . 14-24
THERMOSTAT . . . . . . . . . . . . . . . . . .14-24
REMOVAL AND INSTALLATION . . . . . . . . 14-24
INSPECTION. . . . . . . . . . . . . . . . . . . . . . . . 14-26
WATER PUMP . . . . . . . . . . . . . . . . . .14-27
REMOVAL AND INSTALLATION <4G1> . . 14-27
REMOVAL AND INSTALLATION <4G6> . . 14-28
WATER HOSE AND WATER PIPE . .14-29
REMOVAL AND INSTALLATION <4G1> . . 14-29
REMOVAL AND INSTALLATION <4G6> . . 14-31
INSPECTION. . . . . . . . . . . . . . . . . . . . . . . . 14-32
RADIATOR . . . . . . . . . . . . . . . . . . . . .14-33
REMOVAL AND INSTALLATION <4G1> . . 14-33
REMOVAL AND INSTALLATION <4G6> . . 14-35
GENERAL INFORMATION
ENGINE COOLING14-2
GENERAL INFORMATION
M1141000100371
The 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 circu
-
lation type in which the water pump pressurizes cool-
ant and circulates it throughout the engine. If the
coolant temperature exceeds the prescribed temper
-
ature, 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 crank
-
shaft. The radiator is the corrugated fin, down flow
type.
ItemSpecification
RadiatorPerformance kJ/h4G13Standard vehicles137,720
Vehicles with capacity up radiator
(option)161,288
4G18Standard vehicles161,288
Vehicles with capacity up radiator
(option)181,800
4G63181,800
A/T oil coolerPerformance kJ/h5,651
SERVICE SPECIFICATIONS
M1141000300687
ItemStandard valueLimit
Fan controller VA/C OFF1 or less-
A/C ONRepeat
8.2 ± 0.7
System voltage ± 2.6
-
High-pressure valve opening pressure of radiator cap kPa93 − 123Minimum 83
Range of coolant antifreeze concentration of radiator %30 − 60-
ThermostatValve opening temperature of
thermostat
°C
4G188 ± 1.5-
4G682 ± 1.5-
Full-opening temperature of
thermostat
°C
4G1100-
4G695-
Valve lift mm8.5 or more-
LUBRICANT
ENGINE COOLING14-3
LUBRICANT
M1141000400338
ItemSpecified coolantQuantity L
Engine coolant (including
condense tank)DIAQUEEN SUPER LONG LIFE COOLANT
or an equivalent4G15.0
4G67.0
SEALANTS
M1141000500324
ItemSpecified sealant
Cylinder block drain plug3M Nut Locking Part No.4171 or equivalent
Water pump <4G1>, Thermostat case
<4G6>, Cooling water outlet hose fitting
<4G6>MITSUBISHI GENUINE Part No.MD970389 or equivalent
SPECIAL TOOLS
M1141000600581
ToolNumberNameUse
B991502
MB991502M.U.T. -II sub
assemblyReading diagno sis co de
AC200625
Cylinder block
drain plug
AC
ON-VEHICLE SER VICE
ENGINE COOLING14-22
5.App l y the designa ted sealant to t he scre w area of
th e cylin der block drain plu g , and then tighten to
th e st and ard torq ue.
Sp e c ified s ealant: 3 M Nut Loc king Part
No. 4171 o r e quivale n t
Ti ghtenin g torque:
40 ± 5 N⋅m <4G1>
44 ± 5 N⋅m <4G6>
6.Securely tighten t he drain plug of t he radiator .
7.Reinst all the ra diato r con denser t ank.
CAUTION
Do not use alcohol or methanol anti-freeze or any
engine coolants mixed with alcohol or methanol
anti-freeze. The use of an improper anti-freeze
can cause corrosion of the aluminium compo
-
nents.
AC303612AB
MB991871
AIR HOSE
8. By referring to the section on coolant, select an
appropriate concentration for safe operating
temperature within the range of 30 to 60%. Use
special tool LLC changer (MB991871) to refill the
coolant. A convenient mixture is a 50% water and
50% antifreeze solution (freezing point:
−31°C).
Recommended antifreeze: DIAQUEEN SUPER LONG LIFE COOLANT or equivalent
Quantity:
5.0 L <4G1>
7.0 L <4G6>
NOTE: For how to use special tool MB991871,
refer to its manufacturer’s instructions.
9. Reinstall the radiator cap.
10.Start the engine and let it warm up until the thermostat opens.
11.After repeatedly revving the engine up to 3,000 r/min several times, then stop the engine.
12.Remove the radiator cap after the engine has become cold, and pour in coolant up to the brim.
Reinstall the cap.
CAUTION
Do not overfill the radiator condenser tank.
13.Add coolant to the radiator condenser tank between the "F" and "L" mark if necessary.
CONCENTRATION MEASUREMENT
M1141001100352
Measure the temperature and specific gravity of the
engine coolant to check the antifreeze concentration.
Standard value: 30 − 60% (allowable concentra-
tion range)
Recommended antifreeze: DIAQUEEN SUPER
LONG LIFE COOLANT or equivalent
CAUTION
If the concentration of the anti-freeze is below
30%, the anti-corrosion property will be
adversely affected. In addition, if the concentra
-
tion is above 60%, both the anti-freezing and
engine cooling properties will decrease, affecting
the engine adversely. For these reasons, be sure
to maintain the concentration level within the
specified range.
COOLING FAN MOTOR DRIVE CONTROL
UNIT CHECK
M1141006100250
1. Remove the cooling fan motor drive control unit connector.
AC103195
Y1716AU
1
23
AC
Cooling fan motor
drive control unit
2. Turn the ignition switch to the "ON" position, and
measure the voltage between terminal 1 and 3 at
the harness side connector.
Standard value: system voltage
THERMOSTAT
ENGINE COOLING14-24
COOLING FAN MOTOR CHECK
M1141007100220
1
2
AC303501AB
Cooling fan motor drive control unit
Cooling fan motor
(L.H.) connector
1
2
AC303502AB
Cooling fan motor
drive control unit
Cooling fan motor
(R.H.) connector
<4G1 with A/C>
1. Remove the cooling fa n mot o r co nnector .
2.Check t o see that t he co oling fan motor of the
ra diato r turns wh en ap plying b a ttery power
b e tween th e con nect o r terminal 1 and 2 of t he
cooling fa n mo tor . Also ch eck to see tha t there is
n o abno rmal soun d co min g from the cooling fa n
motor a t this time.
3.If the cooling fan moto r is defective, replace it.
(Refe r to
P.14-33) <4G1> (Refer to P.14-35)
<4G6>.
THERMOSTA T
REMOVA L AND INST ALLA TION
M1141 0024 0044 2
Pre-removal and Post-installation Operation
•Engine Coolant Draining and Refilling (Refer to P.14-21).
•Air Cleaner Assembly Removal and Installation (Refer to
GROUP 15
P.15-3).
•Battery Removal and Installation
AC203409AC
4
3
6
7
22 ± 4 N·m
<4G1>
AC301429
1
2 36
7
13 ± 2 N·m
AD
5
<4G6>
Removal steps
1.Water temperature gauge unit
connector <4G6>
2.Water temperature sensor unit
connector <4G6>
<>>B<<3.Radiator lower hose connection
4.Engine control oxygen sensor
connector and connector bracket
<4G1>
5.Control wiring harness clip <4G6>
6.Cooling water inlet hose fitting
>>A<<7.Thermostat
THERMOST
A T
ENGINE COOLING14-25
REMOV A L SER V ICE POINT
<> RADIAT OR LOW E R HOSE DIS-
CONNECTION
AC200641AC
Mating marks
Make mating marks on the rad i ator lower ho se an d
the hose clamp. Disconn
ect t he radiator lower hose.
INSTALLA T ION SER VICE POINTS
>>A<< THERMOSTA T INST ALLA TION
CAUTION
Make absolutely sure that no oil adheres to the
rubber ring of the thermostat. Also do not fold or
scratch the rubber ring during installation.
AC000279
Jiggle valve
Rubber ring
AB
Install the thermostat so that the jiggle valve is facing
straight up. Be careful not to fold or scratch the rub
-
ber ring.
THERMOSTAT
ENGINE COOLING14-26
>>B<< RADIATOR LOWER HOSE
CONNECTION
AC200642
Mating marks
Projection
Cooling water inlet
hose fitting
AH
1.In sert ra diato r lower h o se a s fa r as th e projection
of the Cooling wa ter inlet ho se fitting .
2.Align the mating marks on the radiator lower hose
an d hose clamp, and then connect the radia t or
lower hose.
INSPECTION
M1 141 0025 0042 7
THERMOSTA T CHECK
ACX00400
AB
1.Imme rse th e thermost at in water , and h eat the
wate r wh ile stirring. Ch eck the th ermost a t va lve
o penin g temperatu r e.
St andard va lue:
88 ± 1.5°C <4G1 >
82 ± 1.5°C <4G6 >
ACX00401 AC
Valve lift
2.
Check t hat the amo unt of valve lif t is at the
st a ndard valu e when th e water is at the
fu ll-o penin g temperatu r e.
NOTE: Meas ure the valve height when the the r-
mostat is fu lly closed , and use t h is measurement
to
comp are the valve h e ight wh en the thermost at
is fully open.
St andard va lue:
100°C <4G1>
95°C <4G6>
Amou nt of val ve lif t: 8 . 5 mm or more
WATER HOSE AND WATER PIPE
ENGINE COOLING14-29
WATER HOSE AND WATER PIPE
REMOVAL AND INSTALLATION <4G1>M1141003300415
Pre-removal and Post-installation Operation
•Under Cover Removal and Installation
•Engine Coolant Draining and Supplying (Refer to P.14-21).
•Air Cleaner Assembly Removal and Installation (Refer to
GROUP 15 P.15-3).
•Thermostat Removal and Installation (Refer to P.14-24).
AC203411
1
2 3
4
5
6
7
8
10
9
13 ± 2 N·m
23 ± 4 N·m
13 ± 2 N·m
N
N
AC
1112
13
N
Removal steps
1.Water temperature sensor unit
connector
2.Water temperature gauge unit
connector
3.Control wiring harness and harness
bracket
<>>>B<<4.Radiator upper hose connection
5.Throttle body water feed hose
6.Thermostat case assembly
7.Thermostat case gasket
>>A<<8.Cooling water line O-ring
9.Control wiring harness clamp
10.Throttle body water return hose
11 .Heater water hose connection
12.Water pump inlet pipe
>>A<<13.Cooling water line O-ring
REMOV
A L SER VICE POINT
<> RADIAT OR UPPER HOSE DISCON-
NECTION
AC200641AC
Mating marks
After making matin g ma rks on the radia t or upp er
hose
and h o se clamp, disconnect the radia t or upp er
hose
.