Here's why:
* The Head Gasket's Role: The head gasket seals the combustion chambers from the cooling system and the oil system. It prevents coolant (antifreeze) and oil from mixing.
* A Blown Head Gasket: If this gasket fails, it creates a pathway between the cooling system (containing antifreeze) and the oil system (containing engine oil). This allows antifreeze to leak into the oil.
Other less likely, but possible, causes include:
* Cracked Cylinder Head: A crack in the cylinder head can also allow coolant to leak into the oil.
* Cracked Engine Block: Similar to a cracked cylinder head, a crack in the engine block can lead to coolant mixing with the oil. This is less common than a head gasket failure.
Why this is serious: Mixing antifreeze and oil severely degrades the lubricating properties of the oil, leading to:
* Engine damage: Lack of proper lubrication causes increased friction, leading to premature wear and tear on engine components. This can quickly lead to catastrophic engine failure.
* Corrosion: Antifreeze is corrosive and can damage engine parts.
What to do: If you find antifreeze in your engine oil, do not run the engine. Have it towed to a mechanic immediately for diagnosis and repair. Continuing to run the engine with contaminated oil will likely cause irreparable damage. The mechanic will likely need to perform a pressure test to pinpoint the exact source of the leak.
