PINPOINT TEST B : The Engine Overheats
- 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 Inspection and Verification. Refer to Engine Cooling .
Were any concerns found?
Yes REPAIR as needed. TEST the system for normal operation. No GO to B2. - B2 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 B3. - B3 CHECK THE ENGINE COOLANT LEVEL
- Ignition OFF.
- Visually check the engine coolant level in the degas bottle.
Is the engine coolant level within specification?
Yes GO to B4. No ADJUST the engine coolant level as necessary. GO to B4. - B4 PRESSURE TEST THE ENGINE COOLING SYSTEM
- Pressure test the engine cooling system. Refer to Engine Cooling .
Does the engine cooling system leak externally?
Yes REPAIR or INSTALL new components. TEST the system for normal operation. No GO to B5. - B5 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 REFER to Engine System - General Information , Symptom Chart: Engine Performance. No GO to B6. - B6 CHECK THE ENGINE OIL FOR COOLANT
- Remove the oil level indicator from the engine.
Is coolant evident in the oil?
Yes REFER to Engine System - General Information , Symptom Chart: Engine Performance. No GO to B7. - B7 CHECK THE COOLING SYSTEM FOR COMBUSTION GASES
- Using UVU560000-R, following the instructions supplied with the tester, check the coolant for combustion gases.
Are combustion gases present?
Yes REFER to Engine System - General Information , Symptom Chart: Engine Performance. No GO to B8. - B8 CHECK COOLANT CONDITION
- Check the coolant for dirt, rust or contamination and check the coolant concentration using 300-ROB75240.
Is the coolant condition OK?
Yes GO to B9. No FLUSH the engine cooling system. Refer to Cooling System Flushing . TEST the system for normal operation. - B9 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 B10. No DIAGNOSE the electric cooling fan operation. REFER to the ENGINE CONTROLS - SYMPTOM CHARTS (EXCEPT DIESEL & HYBRID) . - B10 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 B11. No INSTALL a new coolant pump. TEST the system for normal operation. - B11 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 temperature gauge operation. Go to Pinpoint Test D . No GO to B12. - B12 VISUALLY INSPECT THE THERMOSTAT
- Carry out the thermostat visual inspection. Refer to Engine Cooling .
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.