| DEFINITION: The engine temperature lamp comes on and stays on, or temperature gage shows hot, or coolant overflows from the surge tank onto the ground while the engine is running. |
| 1 | Check for a loss of coolant. Refer to Engine Overheating . Is there a loss of coolant? | Go to Step 2 | Go to Step 3 |
| 2 | Fill the system to the specified level. Refer to Draining and Filling Cooling System . Does the engine still overheat? | Go to Step 3 | System OK |
| 3 | Check for kinked or pinched surge tank hoses, especially at the radiator. Are any surge tank hoses kinked or pinched? | Go to Step 4 | Go to Step 5 |
| 4 | Relieve any kinks by rerouting the hoses. Replace the hoses, if necessary. Does the engine still overheat? | Go to Step 5 | System OK |
| 5 | Check for loose, missing, or damaged radiator air seals or deflectors. Are there any loose, missing, or damaged radiator air seals or deflectors? | Go to Step 6 | Go to Step 7 |
| 6 | Repair or replace any loose, missing, or damaged radiator air seals or deflectors. Does the engine still overheat? | Go to Step 7 | System OK |
| 7 | Check the coolant concentration. Does the coolant concentration test correctly? | Go to Step 9 | Go to Step 8 |
| 8 | Replace the coolant, if necessary. Refer to Draining and Filling Cooling System . Does the engine still overheat? | Go to Step 9 | System OK |
| 9 | Important: Use the correct pressure cap. Check the system for loss of pressure. Is there a loss of pressure? | Go to Step 10 | Go to Step 11 |
| 10 | Repair any leaks, as necessary. Does the engine still overheat? | Go to Step 11 | System OK |
| 11 | Check for a faulty engine coolant temperature (ECT) sensor. Is the ECT sensor faulty? | Go to Step 12 | Go to Step 13 |
| 12 | Replace the ECT sensor. Refer to Engine Coolant Temperature Sensor Replacement . Does the engine still overheat? | Go to Step 13 | System OK |
| 13 | Check the radiator for any air flow obstructions or bent fins. Is there any airflow obstruction or bent fins? | Go to Step 14 | Go to Step 15 |
| 14 | Remove or relocate add-on parts that block air flow to the radiator. Clean any debris from the radiator core. Does the engine still overheat? | Go to Step 15 | System OK |
| 15 | Check for any blocked cooling system passages. Are there any blocked cooling system passages? | Go to Step 16 | Go to Step 17 |
| 16 | Remove any obstruction. Flush the cooling system as required. Refer to Flushing . Refill the coolant. Refer to Draining and Filling Cooling System . Does the engine still overheat? | Go to Step 17 | System OK |
| 17 | Check for an inoperative cooling fan. Is the cooling fan inoperative? | Go to Step 18 | Go to Step 19 |
| 18 | Replace the cooling fan. Refer to Cooling Fan and Shroud Replacement . Does the engine still overheat? | Go to Step 19 | System OK |
| 19 | Check for a thermostat that is stuck closed. Is the thermostat stuck closed? | Go to Step 20 | Go to Step 21 |
| 20 | Replace the thermostat. Refer to Thermostat Replacement . Does the engine still overheat? | Go to Step 21 | System OK |
| 21 | Check for a faulty water pump. The impeller blades may be eroded or broken. Is the water pump faulty? | Go to Step 22 | -- |
| 22 | Replace the water pump. Refer to Water Pump Replacement . Does the engine still overheat? | -- | System OK |
