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 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 - 2.5L -- FUSION & MILAN (EXCEPT HYBRID) article for 2.5L engines, ELECTRONIC ENGINE CONTROLS - 3.0L (4V) -- FUSION & MILAN article for 3.0L (4V) engines or ELECTRONIC ENGINE CONTROLS - 3.5L -- FUSION & MKZ article for 3.5L engines.
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 AND TRANSMISSION FLUID FOR COOLANT
- Remove the oil level indicators from the engine and the transmission.
- Is coolant evident in the oil or transmission fluid?
  - Yes : If coolant is in the engine oil, GO to ENGINE SYSTEM - GENERAL INFORMATION article. If coolant is in the transmission fluid, INSTALL a new radiator. REPAIR the transmission as necessary. Refer to appropriate Automatic Transmission article(s) for procedure(s).
  - 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 ENGINE CONTROLS - INTRODUCTION - GASOLINE MODELS service information.
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 ECT gauge operation. REFER to INSTRUMENTATION, MESSAGE CENTER & WARNING CHIMES -- FUSION, MILAN & MKZ article.
  - No : For 3.5L engines, GO to B13. For 2.5L and 3.0L engines, GO to B14.
B13 CHECK THE ENGINE VENT HOSE CHECK VALVE
- Disconnect the engine vent hose from the engine and degas bottle.
- Using a light, look inside the end of the vent hose that connects to the engine. A check valve should be installed 50 mm (1.96 in) from the end of the hose.
- Using regulated compressed air, confirm air flows freely from the engine end to the degas bottle end.
- Using regulated compressed air, confirm air does not flow from the degas bottle end to the engine end.
- Is the check valve installed in the vent hose and does air flow through in one direction and not the other?
  - Yes : GO to B14.
  - No : INSTALL a new engine vent hose. TEST the system for normal operation.
B14 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.