Page 346 of 1082
01-22
7. COOLING SYSTEM
Coolant reservoir
Water pump assembly
The water pump is driven by the engine drive belt and supplies
the coolant to each area of the engine.
Thermostat assembly
When the engine coolant
reaches 90˚C, the
thermostat starts to open (fully
open at 100˚C) and lets the
coolant flow to the radiator to
maintain the engine
temperature.
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01-230000-00
Coolant outlet port
Coolant temperature sensor
Measures the coolant temperature
and sends the result to the engine
ECU.
Radiator assembly
Releases heat through fins and cools down the
hot coolant as the coolant passes through the
tube of the radiator core.FAN
Circulates the fresh air forcibly to
exchange heat with the radiator core fin.
Page 413 of 1082
06-51443-01
1. OVERVIEW
The ignition system is to supply high voltage generated from the ignition coil to the spark plug. The
G20DF engine is equipped with the independent type direct ignition system that the ignition coil is
installed in each cylinder.
The basic ignition timing in each cylinder is determined by the signals from camshaft position sensor and
crankshaft position sensor.
This ignition system controls the electronic ignition timing received from the engine ECU. To control the
ignition timing precisely, the ECU use the information below:
Engine load
Coolant temperature
Intake air temperature
Engine rpm
Camshaft position sensor (CPS)
Crankshaft position sensor (CKS) -
-
-
-
-
-
If the signal from the camshaft position sensor is not delivered to the engine ECU, the ignition coil and
fuel system cannot be operated.
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06-71443-01
Electric throttle valveT-MAP sensorAccelerator pedal position
sensor
Coolant temperature
sensor
Engine ECU
Crankshaft position
sensor
Page 426 of 1082
08-32112-01
1. SPECIFICATION
Description Specification
Cooling system Type Water cooling, forced circulation
Coolant Capacity Approx. 8.0 ~ 8.5 L
RadiatorCore size 740W X 378.9H X 27T
Flow type Cross flow
AntifreezeType SYC 1025 (LLC)
Mixing ratio 50:50 (water:antifreeze)
Cooling fan moduleType Electric
Capacity 180 W + 120 W
Control type Series: low speed, Parallel: high speed
Coolant reservoirMin. capacity 1.6 L
Circulation Closed roof type
Pressure cap Screw type, 1.4 bar
ThermostatType Wax pallet type
Opening temperature90℃
Fully open temperature100℃
Valve lift 8mm
Page 427 of 1082

08-4
Problem Possible Cause Action
Coolant
level is too low
Coolant
temperature is
too high
2. INSPECTION
Leak from the radiator
Leak from the coolant auxiliary tank
Leak from the heater core -
-
-
Leak from the water inlet cap
Leak from the thermostat housing -
-Reconnect the hose or replace the
clamp
Change the hose -
- Leak from the coolant hose connections
Damaged coolant hose -
-
Change the gasket
Change the water pump -
- Leak from the water pump gasket
Leak from the water pump internal seal -
-
Tighten the bolts to the specified
torque
Change the cylinder head gasket -
- Incorrect tightening torque of the cylinder
head bolts
Damaged cylinder head gasket -
-Change the water inlet cap gasket
Change the thermostat sealing -
-
Coolant leakage (Coolant level is low)
Improper coolant mixture ratio
Kinked coolant hose -
-
-Add coolant
Check the coolant concentration
(Anti-freeze)
Repair or replace the hose -
-
-
Defective thermostat
Defective water pump
Defective radiator
Defective coolant auxiliary tank or tank
cap -
-
-
-Change the thermostat
Change the water pump
Change the radiator
Change the coolant auxiliary tank or
tank cap -
-
-
-Change the radiator
Change the coolant auxiliary tank
Change the heater -
-
-
Cracks on the cylinder block or
cylinder head
Clogged coolant passages in the
cylinder block or cylinder head -
-Change cylinder block or cylinder
head
Clean the coolant passage -
-
Clogged radiator core -
Replace the sensor or repair the
related wiring - Improper operation of cooling fan -Clean the radiator core -
Defective temperature sensor or faulty
wiring -Replace the cooling fan or repair the
related circuit -
Page 428 of 1082
08-52112-01
Problem Possible Cause Action
Coolant
temperature is
too low
Thermostat is stuck open -
Replace the cooling fan or repair the
related circuit -
Improper operation of cooling fan -
Replace the sensor or repair the
related wiring -
Defective temperature sensor or faulty
wiring -Change the thermostat -
Page 430 of 1082
08-72112-01
2) Leak Test
Release the pressure in the system by
loosening the pressure cap of the coolant
reservoir slightly. Then, remove the pressure
cap completely. A.
Never open the cap until the coolant
temperature becomes under 90℃ to
prevent any burn.
Add the coolant so that the coolant level is
between MAX and MIN mark on the coolant
auxiliary tank.
Connect the tester to the tank filler and apply
pressure (1.4 bar).
Check all the coolant hoses, pipes and
connections for leaks when the pressure of
the tester drops, and replace or tighten, if
necessary. B.
C.
D.
3) Thermostat
Immerse the thermostat into the water. Heat the
water and check the valve opening temperature.
Valve opening
temperature90±2℃