Pinpoint Test B: The Engine Overheats

WARNING: This page is about a different car, the 2011 Mercury Milan, 2011 Lincoln MKZ, and 2011 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.

WARNING: Always allow the engine to cool before opening the cooling system. Do not unscrew the coolant pressure relief cap when the engine is operating or the cooling system is hot. The cooling system is under pressure; steam and hot liquid can come out forcefully when the cap is loosened slightly. Failure to follow these instructions may result in serious personal injury.

B1 CARRY OUT INSPECTION AND VERIFICATION
- Carry out the INSPECTION AND VERIFICATION procedure in this service information.
- Were any concerns found?
  Yes
  
  REPAIR as needed. TEST the system for normal operation.
  
  No
  
  GO to B2 .
B2 CHECK FOR DTCs
- Check for DTC P0217, P1285 or P1299.
- Is DTC P0217, P1285 or P1299 present?
  YES
  
  GO to B3 .
  
  No
  
  Actual engine overheating has not been verified. CHECK the Engine Coolant Temperature (ECT) gauge operation. REFER to INSTRUMENTATION, MESSAGE CENTER & WARNING CHIMES -- FUSION, MILAN & MKZ article. If any other PCM DTCs are retrieved, REFER to ELECTRONIC ENGINE CONTROLS - FUSION HYBRID, MILAN HYBRID & MKZ HYBRID article.
B3 CHECK FOR AN AIRFLOW OBSTRUCTION
- Check the radiator or A/C condenser for an external obstruction such as leaves or cardboard.
- Is an obstruction present?
  YES
  
  REMOVE the obstruction. TEST the system for normal operation.
  
  No
  
  GO to B4 .
B4 CHECK THE ENGINE COOLANT LEVEL
NOTE: Allow the engine to cool before checking the coolant level.
- Ignition OFF.
- Visually check the engine coolant level in the degas bottle.
- Is the engine coolant level within specification?
  YES
  
  GO to B5 .
  
  No
  
  ADJUST the engine coolant level as necessary. GO to B5 .
B5 PRESSURE TEST THE ENGINE COOLING SYSTEM
- Pressure test the engine cooling system. Refer to COMPONENT TESTS , COOLING SYSTEM PRESSURE TEST in this service information.
- Does the engine cooling system leak externally?
  YES
  
  REPAIR or INSTALL new components. TEST the system for normal operation.
  
  No
  
  GO to B6 .
B6 CHECK THE ENGINE COOLANT FOR AN INTERNAL LEAK
- Inspect the engine coolant in the degas bottle for signs of engine oil.
- Is engine oil evident in the coolant?
  YES
  
  If engine oil is evident, GO to ENGINE SYSTEM - GENERAL INFORMATION article for engine diagnosis.
  
  No
  
  GO to B7 .
B7 CHECK THE ENGINE OIL FOR COOLANT
- Remove the oil level indicator from the engine.
- Is coolant evident in the oil?
  YES
  
  If coolant is in the engine oil, GO to ENGINE SYSTEM - GENERAL INFORMATION article.
  
  No
  
  GO to B8 .
B8 CHECK THE COOLING SYSTEM FOR COMBUSTION GASES
- Using a cooling system combustion gas leak tester, following the instructions supplied with the tester, check the coolant for combustion gases.
- Are combustion gases present?
  YES
  
  GO to ENGINE SYSTEM - GENERAL INFORMATION article for engine diagnosis.
  
  No
  
  GO to B9 .
B9 CHECK COOLANT CONDITION
- Check the coolant for dirt, rust or contamination and check the coolant concentration.
- Is the coolant condition OK?
  YES
  
  GO to B10 .
  
  No
  
  FLUSH the engine cooling system. REFER to COOLING SYSTEM FLUSHING in this service information. TEST the system for normal operation.
B10 CHECK THE ELECTRIC COOLING FAN OPERATION
- Start the engine.
- Place the climate control function selector in the MAX A/C position and the blower motor switch in the HI position.
- Did the electric cooling fan operate?
  YES
  
  GO to B11 .
  
  No
  
  DIAGNOSE the electric cooling fan operation. REFER to INTRODUCTION -- FUSION HYBRID, MILAN HYBRID & MKZ HYBRID article.
B11 CHECK THE COOLANT PUMP OPERATION
- Start the engine.
- Allow the engine to run for 30 minutes. Place the climate control function selector in the MAX HEAT position. Feel the heater outlet hose.
- Is the heater outlet hose hot?
YES

GO to B12 .

No

INSTALL a new coolant pump. TEST the system for normal operation.
B12 CHECK THE THERMOSTAT OPERATION
- Start the engine.
- Allow the engine to run for 30 minutes. Feel the lower radiator hose.
- Is the lower radiator hose hot?
YES

CHECK the engine coolant temperature gauge operation. REFER to INSTRUMENTATION, MESSAGE CENTER & WARNING CHIMES -- FUSION, MILAN & MKZ article.

No

GO to B13 .
B13 VISUALLY INSPECT THE THERMOSTAT
- Carry out the Thermostat Visual Inspection in the Component Tests portion of this service information.
- Is the thermostat damaged?
  YES
  
  INSTALL a new thermostat. TEST the system for normal operation.
  
  No
  
  INSTALL a new thermostat. TEST the system for normal operation. If the engine still overheats, INSTALL a new radiator. TEST the system for normal operation.