For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
1 | Inspect the thermostat for the following conditions:

• | The thermostat remains open.

• | An incorrect thermostat is installed.

Does either of the above conditions exist?

Go to Step 2

Go to Step 3

2 | Install a new thermostat of the correct type and heat range. Does the engine still fail to reach the normal operating temperature? | Go to Step 3 | System OK
3 | Inspect the coolant level. Is the coolant level below the ADD mark? | Go to Step 4 | Go to Step 5
4 | Add coolant. Does the engine still fail to reach the normal operating temperature? | Go to Step 5 | System OK
5 | Inspect the radiator for the following conditions:

• | Plugging

• | A faulty cap

Does either of the above conditions exist?

Go to Step 6

Go to Step 7

6 |

1. Inspect the radiator or the cap.
2. Replace the cap as necessary.

Does the engine reach the normal operating temperature?

System OK

Go to Step 7

7 | Inspect the cylinder head. Is the cylinder head or block cracked or plugged? | Go to Step 8 | --
8 | Repair the cylinder head or block as necessary. Does the engine reach the normal operating temperature? | System OK | --