Definition: A normal temperature gage is considered to be when the needle is pointing to the middle of the gage.

Normal coolant temperature readings will be expected to vary from 88-104°C (190-220°F).

Did you perform the Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Engine Cooling

1. Ensure that the cooling system is full. Refer to or Cooling System Draining and Filling .
2. Allow the engine/radiator cap to cool.
3. Start the engine with the A/C ON.
4. Inspect the engine cooling fans.

Is either cooling fan on?

Go to Step 3

Go to Step 4

1. Diagnose and repair the cooling fan system. Refer to Symptoms - Engine Cooling
2. Verify the customer complaint.

Does the engine still fail to reach normal operating temperature?

Go to Step 4

System OK

Install the scan tool and compare the coolant temperature reading with the I/P gage.

Does the scan tool coolant temperature reading coincide with a normal temperature gage reading?

Go to Step 6

Go to Step 5

1. Diagnose and repair the coolant gauge system. Refer to Engine Coolant Temperature Gage Inaccurate or Inoperative in Instrument Panel, Gages, and Console.
2. Verify the customer complaint.

Does the engine still fail to reach normal operating temperature?

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 .

Does the thermostat operate properly?

Go to Diagnostic System Check - Engine Cooling

Go to Step 7

1. Replace the thermostat. Refer to Engine Coolant Thermostat Replacement .
2. Verify the customer complaint.

Does the engine still fail to reach normal operating temperature?

Go to Step 8

System OK

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2