DEFINITION: Engine temperature lamp comes on and stays on, or temperature gauge shows hot, or coolant overflows from the surge tank onto the ground while the engine is running

Check for a loss of coolant. Refer to Loss of Coolant .

Is there a loss of coolant?

--

Go to Step 2

Go to Step 3

Fill the system to the specified level. Refer to Cooling System Maintenance Recommendations .

Does the engine still overheat?

--

Go to Step 3

System OK

1. Check to see if any of the surge tank hoses are kinked or pinched, especially at the radiator.
2. Relieve any kinks by rerouting the hoses. Replace the hoses if necessary.

Does the engine still overheat?

--

Go to Step 4

System OK

1. Check for loose, missing or damaged radiator air seals or deflectors.
2. Repair or replace the part(s) as necessary. Refer to Radiator Air Baffle Assemblies and Deflectors .

Does the engine still overheat?

--

Go to Step 5

System OK

Check the coolant concentration. Refer to Coolant Concentration Testing .

Does the engine still overheat?

--

Go to Step 6

System OK

1. Check the system for loss of pressure.
2. Do a system pressure test. Refer to Cooling System Leak Testing .
3. Make sure the correct pressure cap is being used.

Does the engine still overheat?

--

Go to Step 7

System OK

Check for a faulty Engine Coolant Temperature (ECT) sensor. Refer to Electrical Diagnosis.

Does the engine still overheat?

--

Go to Step 8

System OK

1. Check the radiator for any air flow obstruction.
2. Check the radiator for bent fins.
3. Remove or relocate add-on parts that block air flow to the radiator.
4. Clean any bugs, leaves, or snow from the radiator core. Refer to Cooling System Maintenance Recommendations .

Does the engine still overheat?

--

Go to Step 9

System OK

1. Check for blocked cooling system passages.
2. Remove any obstruction. Flush the cooling system as required. Refer to Flushing .
3. Refill the coolant. Refer to Cooling System Draining and Filling .

Does the engine still overheat?

--

Go to Step 10

System OK

1. Check for an inoperative cooling fan. Refer to Electrical Diagnosis.
2. Repair as necessary.

Does the engine still overheat?

--

Go to Step 11

System OK

1. Check for a stuck closed thermostat. Refer to Thermostat Diagnosis .
2. Replace the thermostat as necessary. Refer to Engine Coolant Thermostat Replacement .

Does the engine still overheat?

--

Go to Step 12

System OK

1. Check for a faulty water pump. The impeller blades may be eroded or broken.
2. Replace the water pump as necessary. Refer to Water Pump Replacement .

Is the repair complete?

--

System OK

--