DEFINITION: Either of the following conditions indicate a probable engine overheat condition.

Did you perform the Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Engine Cooling

1. Inspect the level and concentration of the cooling system and fill as necessary. Refer to Cooling System Draining and Filling .
2. Inspect the cooling system for leaks.
3. Repair the cooling system leaks as necessary.

Did you complete the inspection/repair?

Go to Step 3

--

1. Start the engine and allow to the engine to run at approximately 1200 RPM.
2. Use the scan tool in order to verify the overheat condition by viewing the engine coolant temperature.

Does the scan tool coolant temperature reading verify that the engine is overheating?

Go to Step 4

Go to Engine Coolant Temperature Gage Inaccurate or Inoperative in Instrument Panel, Gages and Console

Verify that the engine cooling fans are operating properly. Refer to Cooling System Description and Operation .

Do the cooling fans operate properly?

Go to Step 5

Go to Cooling Fan Inoperative

Perform The following inspections:

1. Inspect the radiator and the A/C condenser cooling fins for debris or any other obstruction.
2. Inspect the drive belt system and the belt tensioner for proper operation in order to ensure that the water pump is rotating properly.
3. Inspect for a loose, damaged, and/or missing air deflector or air baffle.
4. Inspect for a pinched or kinked cooling system hose.
5. Repair the system as necessary.

Does the engine still overheat?

Go to Step 6

System OK

Caution: To avoid being burned, do not remove the radiator cap or surge tank cap while the engine is hot. The cooling system will release scalding fluid and steam under pressure if radiator cap or surge tank cap is removed while the engine and radiator are still hot.

Inspect the thermostat for proper operation. Refer to Thermostat Diagnosis .

Is the thermostat operating properly?

Go to Step 8

Go to Step 7

Replace the thermostat. Refer to Engine Coolant Thermostat Replacement .

Does the engine still overheat?

Go to Step 8

System OK

1. Remove the surge tank cap.
2. Start the engine and inspect for a steady and constant flow of air bubbles in the engine coolant.

Is there a steady and constant flow of air bubbles in the engine coolant?

Go to Engine Overheating

Go to Step 9

The engine overheating may be caused by a cooling system blockage. Flush the cooling system. Refer to Flushing .

Does the engine still overheat?

Go to Step 10

System OK

Important: It is very unlikely that the water pump is the cause of the overheat condition.

If none of the cooling system passages are restricted, and there still seems to be a lack of coolant flowing, replace the water pump. Refer to Water Pump Replacement .

Did you complete the repair?

Go to Step 11

--

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2