NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [SKYACTIV-G 2.0, SKYACTIV-G 2.5]

id0103g3802300

17

COOLING SYSTEM CONCERNS-OVERHEATING
DESCRIPTION
•  Engine runs at higher than normal temperature/overheats.
POSSIBLE CAUSE
•  Engine heat generation amount is excessive
―  Engine speed is high and remains high for continuous long periods
•  PCM DTC is stored
•  Improper indication of low engine coolant temperature indicator light and/or high engine coolant temperature warning light
―  ECT sensor malfunction
―  Instrument cluster malfunction
•  Improper operation of A/C system
•  Cooling fan inoperative
•  Improper engine coolant level
•  Coolant leakage (engine internal, external)
•  Engine coolant performance deterioration
•  Improper water/anti-freeze mixture
•  Poor radiator condition
•  Radiator hose damage
•  Improper or damaged radiator cap
•  Coolant overflow system malfunction
•  Fans reverse rotation
•  Blown fuse
•  Leakage at coolant hoses and/or radiator
•  Leakage around heater unit in passenger compartment
•  Drive belt damage
•  Improper drive belt tension
•  Thermostat malfunction
•  Excessive A/C system pressure

Diagnostic Procedure

STEP

INSPECTION

RESULTS

ACTION
1
INSPECT VEHICLE CONDITION FOR EFFECT ON MALFUNCTION
•  Verify how the customer drives the vehicle by asking the customer the following:
―  Engine speed is high and remains high for continuous long periods like when climbing a long, steep grade.
•  Is the engine generating excessive heat when driven?
Yes
Explain to the customer that the vehicle is normal and give them advice how to use vehicle and provide a specific example of the conditions in which the engine overheats.
No
Go to the next step.
2
DETERMINE IF MALFUNCTION CAUSE IS A/C SYSTEM OR OTHER
•  Start the engine and run it at idle speed.
•  Turn the A/C switch off.
•  Does the A/C compressor disengaged?
Yes
Go to the next step.
No
Perform the symptom troubleshooting “NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY”.
(See NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [SKYACTIV-G 2.0, SKYACTIV-G 2.5].)
3
VERIFY PCM DTC
•  Retrieve any DTCs using the M-MDS.
•  Are any DTCs present?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE [SKYACTIV-G 2.0, SKYACTIV-G 2.5].)
No
Go to the next step.
4
INSPECT ECT SENSOR SIGNAL
•  Access the ECT PID using the M-MDS.
•  Compare the ECT PID and low engine coolant temperature indicator light and high engine coolant temperature warning light operation.
•  Is the ECT PID value same as indicator/warning light readings?
Yes
Go to the next step.
No
Inspect the ECT sensor.
(See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5].)
•  If there is any malfunction:
―  Replace the ECT sensor.
•  If there is no malfunction:
―  Perform the instrument cluster symptom troubleshooting “LOW ENGINE COOLANT TEMPERATURE INDICATOR LIGHT/HIGH ENGINE COOLANT TEMPERATURE WARNING LIGHT ILLUMINATES OR FLASHES CONTINUOUSLY”.
5
INSPECT COOLING FAN CONTROL SYSTEM OPERATION
•  Perform the Cooling Fan Control System Inspection.
•  Does the cooling fan control system operate properly?
Yes
Go to the next step.
No
Repair or replace the malfunctioning part according to the inspection results.
6
INSPECT RELATED PART CONDITION
•  Inspect the following:
―  Engine coolant level
―  Engine coolant performance
―  Water and anti-freeze mixture
―  Radiator condition
―  Collapsed or restricted radiator hoses
―  Radiator pressure cap
―  Coolant overflow system
―  Fan rotational direction
―  Fuses
•  Is there any malfunction?
Yes
Service if necessary.
•  Repeat this step.
No
Go to the next step.
7
INSPECT COOLANT LEAKAGE AT COOLING SYSTEM PART
•  Inspect for leakage at coolant hoses and/or radiator.
•  Is there any leakage?
Yes
Repair or replace the malfunctioning part according to the inspection results.
No
Go to the next step.
8
INSPECT COOLANT LEAKAGE AT HEATER UNIT
•  Inspect for leakage around heater unit in passenger compartment.
•  Is there any leakage?
Yes
Repair or replace the malfunctioning part according to the inspection results.
No
Go to the next step.
9
INSPECT DRIVE BELT
•  Inspect the drive belt.
•  Is there any malfunction?
Yes
Replace the drive belt.
(See DRIVE BELT REMOVAL/INSTALLATION [SKYACTIV-G 2.0, SKYACTIV-G 2.5].)
No
Go to the next step.
10
INSPECT THERMOSTAT
•  Cool down the engine.
•  Remove the thermostat.
•  Inspect the thermostat operation.
•  Is there any malfunction?
Yes
Replace the thermostat.
(See THERMOSTAT REMOVAL/INSTALLATION [SKYACTIV-G 2.0, SKYACTIV-G 2.5].)
No
Reinstall the thermostat.
(See THERMOSTAT REMOVAL/INSTALLATION [SKYACTIV-G 2.0, SKYACTIV-G 2.5].)
The engine coolant temperature and thermostat are normal.
•  Inspect the engine block for leakage or blockage.
•  Repair or replace the malfunctioning part according to the inspection results.
11
Verify the test results.
•  If normal, return to the diagnostic index to service any additional symptoms.
•  If a malfunction remains, inspect the related Service Information and perform the repair or diagnosis.
―  If the vehicle is repaired, troubleshooting is completed.
―  If the vehicle is not repaired or additional diagnostic information is not available, replace the PCM.