Pinpoint Test B : The Engine Overheats
WARNING: This page is about a different car, the 2016 Ford Expedition. 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 article.
Were any concerns found?
Yes REPAIR as needed. No GO to B2. - B2 CHECK FOR PCM 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, and Warning Chimes . If any other PCM DTCs are retrieved, REFER to Electronic Engine Controls . - B3 CHECK FOR AN AIRFLOW OBSTRUCTION AND MISSING AIR DEFLECTORSNOTE: Verify no vehicle front end damage is present.
- Check the radiator or A/C condenser for an external obstruction such as leaves or cardboard and verify all air deflectors are present.
Is an airflow obstruction present or air deflectors missing?
Yes RREPAIR as necessary. No GO to B4. - B4 CHECK THE ENGINE COOLANT LEVELNOTE: Allow the engine to cool before checking the coolant level.
- Ignition OFF.
- Visually check the engine coolant level in the coolant expansion tank.
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 Coolant System Pressure Test .
Does the engine cooling system leak externally?
Yes REPAIR or INSTALL new components. No GO to B6. - B6 CHECK THE PRESSURE RELIEF CAP
- Carry out the Pressure Relief Cap Pressure Test. Refer to Component Test, Pressure Relief Cap Pressure Test in this article.
Is the pressure relief cap OK?
Yes GO to B7. No INSTALL a new pressure relief cap. - B7 CHECK THE ENGINE COOLANT FOR AN INTERNAL LEAK
- Inspect the engine coolant in the coolant expansion tank and the radiator for signs of engine oil or transmission fluid.
Is engine oil or transmission fluid evident in the coolant?
Yes If engine oil is evident, GO to Engine System General Information for engine diagnosis. If transmission fluid is evident, INSTALL a new radiator. REPAIR the transmission as necessary. Refer to the appropriate Automatic Transmission article for the procedure. No GO to B8. - B8 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 . If coolant is in the transmission fluid, INSTALL a new radiator. REPAIR the transmission as necessary. Refer to the appropriate Automatic Transmission article for the procedure. No GO to B9. - B9 CHECK THE COOLING SYSTEM FOR COMBUSTION GASES
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NOTE: Use UView ® Combustion Leak Tester part number UVU560000-R or equivalent.
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 for engine diagnosis. No GO to B10. -
- B10 CHECK COOLANT CONDITION
- Check the coolant for dirt, rust or contamination and check the coolant concentration.
Is the coolant condition OK?
Yes GO to B11. No FLUSH the engine cooling system. REFER to Cooling System Flushing . - B11 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 B12. No DIAGNOSE the electric cooling fan operation. REFER to the Engine Controls - Symptom Charts (Except Diesel & Hybrid) . - B12 CHECK THE COOLANT PUMP OPERATION
- Start the engine.
- Allow the engine to run for 10 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 B13. No INSTALL a new coolant pump. Coolant Pump - B13 CHECK THE THERMOSTAT OPERATIONNOTE: This cooling system uses a cold side thermostat. The coolant in the radiator must reach full operating temperature for the thermostat to remain in an open state.
- 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, and Warning Chimes . No GO to B14. - B14 VISUALLY INSPECT THE THERMOSTAT
- Carry out the Thermostat Visual Inspection.
Is the thermostat damaged?
Yes INSTALL a new thermostat. Thermostat No INSTALL a new thermostat. Thermostat If the engine still overheats, INSTALL a new radiator. Radiator