NO.17 COOLING SYSTEM CONCERNS-OVERHEATING[AJ (3.0L Duratec)]

id0103a7802300

17
Cooling system concerns—overheating
DESCRIPTION
•  The engine runs at higher than normal temperature/overheats.
POSSIBLE CAUSE
•  Improper coolant level
•  Blown fuses
•  Coolant leakage
•  Excessive A/C system pressure
•  Improper water/anti-freeze mixture
•  Fans reverse rotation
•  Poor radiator condition
•  Thermostat malfunction
•  Radiator hoses damage
•  Condenser fan is inoperative.
•  Improper or damaged radiator cap
•  Cooling fan is inoperative.
•  Coolant overflow system malfunction
•  Improper tension of drive belt
•  Drive belt damage
•  Fan control module malfunction

Diagnostic procedure

STEP

INSPECTION

RESULTS

ACTION
1
•  Inspect the following:
―  Engine coolant level
―  Coolant leakage
―  Water and anti-freeze mixture
―  Radiator condition
―  Collapsed or restricted radiator hoses
―  Radiator pressure cap
―  Overflow system
―  Fan rotational direction
―  Fuses
•  Are all items normal?
Yes
Go to the next step.
No
Service if necessary.
Repeat Step 1.
2
•  Connect the M-MDS to the DLC–2.
•  Turn the ignition switch to the ON position (Engine off).
•  Retrieve any DTCs.
•  Is “PASSED” displayed?
Yes
No DTC is displayed:
•  Go to the next step.
No
DTC is displayed:
•  Go to the appropriate DTC test.
3
•  Start the engine and run it at idle speed.
•  Turn the A/C switch on.
•  Does the A/C compressor engage?
Yes
Go to step 5.
No
Inspect the following and repair or replace if necessary:
•  Refrigerant charging amount
•  Open circuit between A/C relay and PCM terminal 69
•  Seized A/C magnetic clutch
•  A/C magnetic clutch malfunction
―  If all items are normal, Inspect the following:
•  Refrigerant pressure switch operation
•  Evaporator temperature sensor and A/C amplifier
•  A/C switch is stuck open.
•  Open or short circuit between refrigerant pressure switch and PCM terminal 41
•  Open circuit of blower motor fan switch and resistor (if blower motor does not operate)
4
•  Start the engine and run it at idle speed.
•  Turn the A/C switch ON.
•  Do cooling fan and condenser fan operate?
Yes
Go to the next step.
No
Cooling fan motor does not operate:
•  Inspect for the following:
―  Cooling fan motor malfunction
―  Cooling fan motor ground open
―  Open circuit between cooling fan motor and fan control module
Condenser fan motor does not operate:
•  Inspect for the following:
―  Condenser fan motor malfunction
―  Condenser fan motor ground open
―  Open circuit between condenser fan motor and fan control module
Both cooling fan and condenser fan do not operate:
•  Inspect for the following:
―  Fan control module malfunction
―  Fan control module ground open
―  Open circuit between fan control module and cooling fan relay
5
•  Is the drive belt normal?
Yes
Go to the next step.
No
Replace the drive belt.
6
•  Is there any leakage around heater unit in the passenger compartment?
Yes
Inspect and service heater for leakage.
No
Go to the next step.
7
•  Is there any leakage at the coolant hoses and/or radiator?
Yes
Replace the malfunctioning part.
No
Go to the next step.
8
•  Cool down engine.
•  Remove the thermostat and inspect operation.
•  Is the thermostat normal?
Yes
Engine coolant temperature and thermostat are normal.
Inspect the engine block for leakage or blockage.
No
Access the ECT PID on M-MDS.
Inspect the both ECT PID and temperature gauge readings.
•  If the temperature gauge on instrument cluster indicates normal range but ECT PID is not same as temperature gauge reading, inspect ECT sensor.
•  If the temperature gauge on instrument cluster indicates overheating but ECT PID is normal, inspect temperature gauge and heat gauge unit.
9
•  Verify the test results.
―  If normal, return to the diagnostic index to service any additional symptoms.
―  If malfunction remains, inspect related Service Information and perform repair or diagnosis.
•  If vehicle is repaired, troubleshooting completed.
•  If vehicle is not repaired or additional diagnostic information is not available, replace the PCM.