Indications of a Blown Head Gasket

by Michelle Nickolaisen
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The head gasket's job is to provide the engine block with an airtight seal and prevent fluids in the engine block from mixing. It also prevents any fluids from gaining access to the combustion chambers, the part of the engine where fuel is exploded. Anyone who has had a broken or "blown" head gasket knows that it can cause some serious problems. Oil residue can build up in the combustion chambers, causing them to fail, and oil seeping into the coolant system causes a vehicle to overheat, causing even more damage. Not fixing a broken head gasket can lead to very costly repairs.

Discolored Oil

White or frothy-looking oil is one sign of a broken head gasket. This can be seen on the engine's dipstick. The milky-looking oil is caused by the head gasket breaking next to the coolant system. Coolant leaks into the oil system and then is circulated with the oil. The coolant degrades the oil's ability to lubricate the engine and causes rapid wearing on the engine's parts. Keep an eye on the color and texture of the oil.

Thick Exhaust

Thick exhaust is another sign of a broken head gasket. Thick and smokey exhaust is caused by the head gasket breaking next to the oil system and leaking oil into the combustion chamber. When this happens, the combustion chamber continues to function (if only for a while), and the oil is burned along with the engine fuel. Oil burns much less cleanly than fuel and creates a thick smoke in the exhaust. The other problem is that oil leaves behind residue that accumulates in the combustion chamber.


Overheating can also be a sign of a broken head gasket. If oil leaks into the coolant system, it will reduce the coolant's ability to properly cool the engine. Oil retains heat much better than coolant, and the radiator will not be able to cool it off as easily. This leads to the engine overheating.

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