DEFINITION: Engine temperature lamp comes ON and stays ON, or the temperature gage shows hot, or coolant overflows from the reservoir onto the ground while the engine is running.

Check for a missing or damaged radiator upper baffle.

Is the baffle missing or damaged?

Go to Step 8

Go to Step 2

Check for a loss of coolant.

Is there a loss of coolant?

Go to Step 3

Go to Step 4

Fill the system to the specified level. Refer to Cooling System Draining and Filling .

Does the engine overheat?

Go to Step 4

System OK

Check for low coolant protection. Refer to Coolant Concentration Testing .

Is the coolant to the correct concentration?

Go to Step 5

Go to Step 8

Check for a loss of system pressure. Refer to Cooling System Leak Testing .

Is there a loss of system pressure?

Go to Step 8

Go to Step 6

Check for a faulty engine coolant temperature (ECT) sensor. Refer to Engine Coolant Temperature Sensor Replacement in Engine Controls.

Is the sensor operating properly?

Go to Step 7

Go to Step 8

Check for a cracked coolant recovery reservoir or a leaking hose. Refer to Cooling System Leak Testing.

Is the reservoir cracked or is the hose leaking?

Go to Step 8

Go to Step 3

Repair or install new parts as necessary, then retest.

Does the engine overheat?

Go to Step 9

System OK

Check for incorrect drive belt tension.

Is the belt to the correct tension?

Go to Step 10

Go to Step 8

Check for a faulty auxiliary water pump.

Is an auxiliary water pump faulty?

Go to Step 8

Go to Step 11

Check for obstructed radiator air flow or bent radiator fins.

Is the radiator air flow obstructed?

Go to Step 8

Go to Step 12

Check for blocked cooling system passages.

Are the cooling system passages blocked?

Go to Step 8

Go to Step 13

Check for improper direction or inoperative cooling fans.

Are the cooling fans and the motors operating correctly?

Go to Step 14

Go to Step 8

Check the thermostat. Refer to Thermostat Diagnosis .

Is the thermostat stuck in the closed position?

Go to Step 15

Go to Step 16

Replace the thermostat. Refer to Thermostat Replacement .

Does the engine overheat?

Go to Step 16

System OK

Check for a faulty engine water pump.

Are the impeller blades broken or eroded?

Go to Step 8

Go to Step 17

Check the radiator cooling capacity.

Is the proper sized radiator being used on the vehicle?

Go to Step 3

Go to Step 18

Consult the current parts catalog. If necessary, replace the radiator. Refer to Radiator Replacement .

Is the repair complete?

System OK