Inspect the thermostat for the following conditions:

Does either of the above conditions exist?

Go to Step 2

Go to Step 3

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

Inspect the coolant level.

Is the coolant level below the ADD mark?

Go to Step 4

Go to Step 5

Add coolant.

Does the engine still fail to reach the normal operating temperature?

Go to Step 5

System OK

Inspect the radiator for the following conditions:

Does either of the above conditions exist?

Go to Step 6

Go to Step 7

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

Inspect the cylinder head.

Is the cylinder head or block cracked or plugged?

Go to Step 8

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Repair the cylinder head or block as necessary.

Does the engine reach the normal operating temperature?

System OK

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