
ON-VEHICLE SERVICE
ENGINE LUBRICATION12-4
ON-VEHICLE SERVICE
ENGINE OIL CHECKM1121000900342
1. Pull out the engine oil level gauge slowly and 
check that the oil level is in the illustrated range.
2. Check that the oil is not excessively dirty, that 
there is no coolant or petrol mixed in, and that it 
has sufficient viscosity.
ENGINE OIL REPLACEMENTM1121001000416
1. Start the engine and allow it to warm up until the 
temperature of the coolant reaches 80 °C to 90 
°C.
2. Remove the engine oil filler cap.
CAUTION
Use care as engine oil could be hot.
3. Remove the engine oil pan drain plug to drain 
engine oil.4. Install a new engine oil pan drain plug gasket so 
that it faces in the direction shown in the 
illustration, and then tighten the engine oil pan 
drain plug to the specified torque.
Tightening torque: 39 ± 5 N⋅m
NOTE: Install the engine oil pan drain plug gasket 
so it faces in the direction shown in the illustration.
5. Refill with specified quantity of engine oil.
Specified Engine Oil (ACEA and API 
classification): ACEA A1, A2 or A3/API SG or 
higher
Total quantity (Includes volume inside engine 
oil filter): 
3.3 L <4G1>
4.3 L <4G6>
6. Install the engine oil filler cap.
7. Check engine oil level.
ENGINE OIL FILTER REPLACEMENTM1121001100383
1. Start the engine and allow it to warm up until the 
temperature of the coolant reaches 80 °C to 90 
°C.
2. Remove the engine oil filler cap.
CAUTION
Use care as engine oil could be hot.
3. Remove the engine oil pan drain plug to drain 
engine oil.
4. Remove the under cover.
ACX00892 AC
Good
MaximumMinimum
<4G1>
AC205268
Maximum MinimumGood
AC
<4G6>
AC208299
Engine oil pan
AC
Engine oip pan
drain plug
Engine oip pan
drain plug
Engine oil
pan side
AC301513 

14-1
GROUP 14
ENGINE COOLING
CONTENTS
GENERAL INFORMATION  . . . . . . . .14-2
SERVICE SPECIFICATIONS . . . . . . .14-2
LUBRICANT . . . . . . . . . . . . . . . . . . . .14-2
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 . . . . . . . . . . .14-22
ENGINE COOLANT LEAK CHECK  . . . . . . 14-22
RADIATOR CAP VALVE OPENING 
PRESSURE CHECK . . . . . . . . . . . . . . . . . . 14-22
ENGINE COOLANT REPLACEMENT  . . . . 14-22
CONCENTRATION MEASUREMENT  . . . . 14-23COOLING FAN MOTOR DRIVE CONTROL 
UNIT CHECK . . . . . . . . . . . . . . . . . . . . . . . . 14-23
FAN CONTROL RELAY CONTINUITY 
CHECK  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-24
COOLING FAN MOTOR CHECK  . . . . . . . . 14-25
THERMOSTAT . . . . . . . . . . . . . . . . . .14-26
REMOVAL AND INSTALLATION  . . . . . . . . 14-26
INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . 14-27
WATER PUMP  . . . . . . . . . . . . . . . . . .14-29
REMOVAL AND INSTALLATION <4G1>  . . 14-29
REMOVAL AND INSTALLATION <4G6>  . . 14-30
WATER HOSE AND WATER PIPE  . .14-31
REMOVAL AND INSTALLATION <4G1>  . . 14-31
REMOVAL AND INSTALLATION <4G6>  . . 14-33
INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . 14-34
RADIATOR . . . . . . . . . . . . . . . . . . . . .14-35
REMOVAL AND INSTALLATION  . . . . . . . . 14-35 

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 

TROUBLESHOOTING
ENGINE COOLING14-5
TROUBLESHOOTING
INSPECTION CHART FOR TROUBLE 
SYMPTOMS
M1141005600360
MB991223 
A: MB991219 
B: MB991220 
C: MB991221 
D: MB991222 Harness set 
A: Test harness 
B: LED harness 
C: LED harness 
adapter
D: ProbeMaking voltage and 
resistance measurement 
during troubleshooting
A: Connector pin contact 
pressure inspection
B: Power circuit inspection
C: Power circuit inspection
D: Commercial tester 
connection
MB991871 LLC changer Coolant refilling Tool Number Name Use
MB991223
A
B
C
D
AC
MB991871
Trouble symptom Inspection 
procedure No.Reference page
Cooling fan (L.H.) and Cooling fan (R.H.) <4G1 (Vehicles with 
A/C)> or A/C condenser fan <4G6> do not operate 1
P.14-6
Cooling fan (L.H.) and Cooling fan (R.H.) <4G1 (Vehicles with 
A/C)> or A/C condenser fan <4G6> do not change speed or stop2
P.14-16
Cooling fan (L.H.) does not operate {When cooling fan (R.H.) 
<4G1> or A/C condenser fan <4G6> operate} 
P.14-20
Cooling fan (R.H.) <4G1> or A/C condenser fan <4G6> does not 
operate {When cooling fan (L.H.) operate} 
P.14-21 

ON-VEHICLE SERVICE
ENGINE COOLING14-22
ON-VEHICLE SERVICE
ENGINE COOLANT LEAK CHECKM1141001000300
WARNING
When pressure testing the cooling system, 
slowly release cooling system pressure to 
avoid getting burned by hot coolant.
CAUTION
•Be sure to completely clean away any 
moisture from the places checked.
•When the tester is taken out, be careful not to 
spill any coolant.
•Be careful when installing and removing the 
tester and when testing not to deform the 
filler neck of the radiator.
1. Check that the coolant level is up to the filler neck. 
Install a radiator tester and apply 160 kPa 
pressure, and then check for leakage from the 
radiator hose or connections.
2. If there is leakage, repair or replace the 
appropriate part.
RADIATOR CAP VALVE OPENING 
PRESSURE CHECK
M1141001300389
NOTE: Be sure that the cap is clean before 
testing. Rust or other foreign material on the cap 
seal will cause an improper reading.
1. Use a cap adapter to attach the cap to the tester.2. Increase the pressure until the indicator of the 
gauge stops moving.
Minimum limit: 83 kPa
Standard value: 93 − 123 kPa
3. Replace the radiator cap if the reading does not 
remain at or above the limit.
ENGINE COOLANT REPLACEMENTM1141001200434
WARNING
When removing the radiator cap, use care to 
avoid contact with hot coolant or steam. 
Place a shop towel over the cap and turn the 
cap counterclockwise a little to let the 
pressure escape through the vinyl tube. 
After relieving the steam pressure, remove 
the cap by slowly turning it 
counterclockwise.
1. Drain the water from the radiator, heater core and 
engine after unplugging the radiator drain plug 
and removing the radiator cap.
2. Drain the water in the water jacket by unplugging 
the drain plug of the cylinder block.
3. Remove the radiator condenser tank and drain 
the coolant.
4. Drain the coolant then clean the path of the 
coolant by injecting water into the radiator from 
the radiator cap area.
ACX01844
Cap adapter
Adapter
AC
AC211643AB
Cap adapter
AC208283AC
Cylinder block
drain plug
<4G1>
Inlet side
AC303355
<4G6>
Inlet side
Cylinder block
drain plug
AB 

ON-VEHICLE SERVICE
ENGINE COOLING14-23
5. Apply the designated sealant to the screw area of 
the cylinder block drain plug, and then tighten to 
the standard torque.
Specified sealant: 3M Nut Locking Part 
No.4171 or equivalent
Tightening torque:
40 ± 5 N⋅m <4G1>
44 ± 5 N⋅m <4G6>
6. Securely tighten the drain plug of the radiator.
7. Reinstall the radiator condenser tank.
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 
components.
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 MEASUREMENTM1141001100352
Measure the temperature and specific gravity of the 
engine coolant to check the antifreeze concentration.
Standard value: 30 − 60% (allowable 
concentration 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 
concentration 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
M1141006100216
1. Remove the cooling fan motor drive control unit 
connector.
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
AC200625
Cylinder block
drain plug
AC
AC303612AB
MB991871
AIR HOSE
AC103195
Y1716AU
1 23
AC
Cooling fan motor
drive control unit 

THERMOSTAT
ENGINE COOLING14-26
THERMOSTAT
REMOVAL AND INSTALLATIONM1141002400442
Pre-removal and Post-installation Operation
•Engine Coolant Draining and Refilling (Refer to P.14-22).
•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> 

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