DEFINITION: Engine temperature lamp comes ON and stays ON, or the temperature gauge shows hot, or coolant overflows from the reservoir 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?

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Go to Step 2

1. Check for weak engine coolant solution.
2. Perform a concentration test. Refer to Coolant Concentration Testing .

Does the engine still overheat?

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Go to Step 3

System OK

1. Check for obstructed radiator air flow or bent radiator fins.
2. If necessary, remove or relocate added-on parts that block air to the radiator. Clean away any bugs, leaves, or other debris.

Does the engine still overheat?

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Go to Step 4

System OK

1. Check for a loss of system pressure.
2. Perform a radiator fill cap pressure test. Refer to Pressure Cap Testing .

Does the engine still overheat?

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Go to Step 5

System OK

1. Check for a faulty Engine Coolant Temperature (ECT) sensor. Refer to one of the following procedures:

•	DTC P0117 Engine Coolant Temperature (ECT) Sensor Circuit Low Voltage in Engine Controls-3.8L.

•	DTC P0118 Engine Coolant Temperature (ECT) Sensor Circuit High Voltage in Engine Controls-3.8L.

•	DTC P0117 Engine Coolant Temperature (ECT) Sensor Circuit Low Voltage in Engine Controls-5.7L.

•	DTC P0118 Engine Coolant Temperature (ECT) Sensor Circuit High Voltage in Engine Controls-5.7L.

2. If necessary, replace the sensor.

Does the engine still overheat?

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Go to Step 6

System OK

1. Check for a damaged coolant recovery reservoir.
2. Check for a leaking or kinked reservoir hose.
3. If necessary, reroute the reservoir hose or replace the recovery reservoir. Refer to Coolant Recovery Reservoir Replacement .

Does the engine still overheat?

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Go to Step 7

System OK

1. Check for a loose accessory drive belt.
2. Check the tension of the drive belt. Refer to the following procedures:

•	Drive Belt Replacement in Engine Mechanical - 3.8L .

•	Drive Belt Replacement - Accessory in Engine Mechanical - 5.7L.

Does the engine still overheat?

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Go to Step 8

System OK

1. Check for advanced or retarded ignition timing.
2. If necessary, adjust the timing.

Does the engine still overheat?

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Go to Step 9

System OK

1. Check for blocked cooling system passages.
2. Flush the cooling system. Refer to Flushing .
3. If necessary, remove and inspect the cylinder head.

Does the engine still overheat?

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Go to Step 10

System OK

1. Check for an incorrect or damaged cooling fan blade(s).
2. Check for the correct fan blade(s) part number.
3. If necessary, replace the fan blade(s). Refer to Engine Cooling Fan Replacement .

Does the engine still overheat?

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Go to Step 11

System OK

1. Check for inoperative cooling fans. Refer to Electric Cooling Fan Diagnosis in Engine Controls - 3.8 L or Electric Cooling Fan Diagnosis in Engine Controls - 5.7 L.
2. If necessary, replace the cooling fan and motor. Refer to Engine Cooling Fan Replacement .

Does the engine still overheat?

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Go to Step 12

System OK

1. Check for a stuck closed thermostat. Refer to Thermostat Diagnosis .
2. If necessary, replace the thermostat. Refer to Engine Coolant Thermostat Replacement .

Does the engine still overheat?

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Go to Step 13

System OK

1. Check for a faulty coolant pump.
2. If necessary, replace the coolant pump. Refer to Water Pump Replacement .

Does the engine still overheat?

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Go to Step 14

System OK

1. Check the radiator cooling capacity.
2. Check if the radiator is the proper size for the vehicle.
3. If necessary, determine the proper radiator size and replace the radiator. Refer to Radiator Replacement .

Is the repair complete?

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System OK

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