For 1990-2009 cars

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 |

1. Ensure that the cooling system is full. Refer to Cooling System Draining and Filling .
2. Start the engine and inspect.

Is there excessive white smoke from the exhaust and/or does the engine run rough?

--

Go to Step 8

Go to Step 2

2 | Road test the vehicle and allow the engine to reach full operating temperature. Does the engine overheat? | -- | Go to Engine Overheating | Go to Step 3
3 | Remove the oil level indicator and inspect. Is there engine coolant or a creamy/milky substance on the engine oil level indicator? | -- | Go to Step 4 | Go to Step 5
4 | Important: Ensure that the cause of the creamy or milky substance is not caused by short drive cycles or a faulty thermostat. Either of these conditions will cause creamy or milky deposits to form in the engine oil because the engine cannot reach full operating temperature in order to dissipate the condensation/moisture.

Does the engine reach full operating temperature during all of the vehicle drive cycles and does the thermostat operate properly?

--

Go to Step 8

Go to Step 5

5 | Inspect for signs of a coolant leak. Does the vehicle exhibit a coolant leak? | -- | Go to Step 6 | Go to Step 7
6 | Repair or replace the leaking component(s) as necessary. Has the repair been performed? | -- | Go to Step 9 | --
7 |

1. Pressure test the cooling a cooling system. Refer to Cooling System Leak Testing .
2. While the cooling system is pressurized, inspect for a coolant leak. Repair or replace the leaking component(s) as necessary.

Has the repair been performed?

--

Go to Step 9

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8 | The probable cause of the coolant loss is an engine internal coolant leak. If the spark plug electrodes or the porcelain surrounding the spark plug electrodes exhibit signs of coolant, replace the intake manifold or the applicable cylinder head gasket(s) as necessary.

However, any of the following components may be the cause of the engine internal coolant leak.

1. Cylinder head gasket/cylinder head
2. Engine oil cooler (with RPO V08)
3. Intake manifold gasket/intake manifold

Replace the leaking component(s) as necessary.

Has the repair been performed?

--

Go to Step 9

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9 |

1. Ensure that the cooling system is full. Refer to Cooling System Draining and Filling .
2. Road test the vehicle, and/or pressure test the cooling system and inspect as necessary in order to duplicate the customer complaint.

Does the vehicle still exhibit coolant loss?

--

Go to Step 1

System OK