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 operation of A/C system
•  Insufficient air blow volume
―  Cooling fan inoperative
―  Fan rotation speed decreases (such as generator malfunction) due to battery voltage decrease
•  Cooling system cap malfunction
•  Cooling fan motor assembly malfunction
•  Cooling fan motor connector malfunction
•  Improper indication of low engine coolant temperature indicator light and/or high engine coolant temperature warning light
―  ECT sensor malfunction
―  Instrument cluster malfunction
•  Blown fuse
•  Engine coolant system malfunction
―  Engine coolant performance deterioration
―  Coolant leakage (engine internal, external)
―  Improper water/anti-freeze mixture
―  Thermostat malfunction (not fully open)
―  Radiator malfunction (clogging)
•  Improper engine coolant level
―  Leakage around heater unit in passenger compartment
•  Drive belt damage

Diagnostic Procedure

STEP

INSPECTION

RESULTS

ACTION
1
INSPECT EFFECT OF VEHICLE CONDITION FOR 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 specific example of the conditions in which the engine overheats.
No
Go to the next step.
2
VERIFY PCM DTC
•  Retrieve any DTCs using the M-MDS.
•  Are any DTCs present?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE [PCM (SKYACTIV-G 2.0, SKYACTIV-G 2.5)].)
No
Go to the next step.
3
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].)
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 COOLING SYSTEM CAP
•  Inspect the cooling system cap.
•  Is there any malfunction?
Yes
Replace the cooling system cap.
No
Go to the next step.
7
INSPECT RELATED PART CONDITION
•  Inspect the following:
―  Engine coolant level
―  Engine coolant performance
―  Coolant leakage (engine internal, external)
―  Water and anti-freeze mixture
―  Thermostat (not fully open)
―  Radiator (clogging)
―  Fuses
•  Is there any malfunction?
Yes
Service if necessary.
•  Repeat this step.
No
Go to the next step.
8
VERIFY IF MALFUNCTION CAUSED BY LACK OF ENGINE COOLANT
•  Inspect the engine coolant level.
•  Is there any malfunction?
Yes
Add engine coolant and verify that there is no engine coolant leakage.
(See ENGINE COOLANT REPLACEMENT [SKYACTIV-G 2.0, SKYACTIV-G 2.5].)
(See ENGINE COOLANT LEAKAGE INSPECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5].)
•  If there is any malfunction:
―  Repair or replace the malfunctioning part according to the inspection results.
No
Go to the next step.
9
DETERMINE IF MALFUNCTION CAUSE IS THERMOSTAT OR OTHER
•  Verify the radiator hose tension.
Warning
•  To prevent burns, use a cloth with your hand to verify the tension of the radiator hose.
•  After the engine warms up, does the engine coolant circulate to the radiator hose?
Yes
Go to Step 11.
No
Go to the next step.
10
INSPECT THERMOSTAT
•  Inspect the thermostat.
•  Is the thermostat normal?
Yes
Inspect the water pump.
•  If there is any malfunction:
―  Repair or replace the malfunctioning part according to the inspection results.
No
Replace the thermostat.
(See THERMOSTAT REMOVAL/INSTALLATION [SKYACTIV-G 2.0, SKYACTIV-G 2.5].)
11
INSPECT DRIVE BELT
•  Inspect the drive belt.
•  Is the indicator mark on the drive belt auto tensioner within the normal range?
Yes
Go to the next step.
No
Replace the drive belt.
(See DRIVE BELT REMOVAL/INSTALLATION [SKYACTIV-G 2.0, SKYACTIV-G 2.5].)
12
INSPECT RADIATOR FOR CLOGGING
•  Inspect for clogging in the radiator.
•  Is there any malfunction?
Yes
Repair or replace the malfunctioning part according to the inspection results.
No
Replace the engine coolant.
(See ENGINE COOLANT REPLACEMENT [SKYACTIV-G 2.0, SKYACTIV-G 2.5].)
13
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.