Signs of blown cylinder head

In short the cylinder head gasket can "blow" in various places giving a range of symptoms. If the gasket blows between the waterways and the outside of the engine water will seep out under pressure as the engine warms. You will note a loss of coolant. If the gasket blows between the oil and water ways you can find either water in the oil (usually seen as a white milky look to the oil on the dipstick) a rise in oil quantity as the water gets into the sump and a loss of water from the cooling system. As the cooling system runs under pressure it is likelier that you will see water in the oil than vice versa. That said there is sometimes a negative pressure in the cooling system as the engine cools which can draw oil back into the cooling system staining the coolant. If the gasket is blown between one of the combustion chambers and the cooling water ways you will experience high pressures building up in the cooling system. The raditor cap will lift and vent water into the overflow tank at relatively low coolant temperatures. Cracked or warped cylinder heads, cylinder liners or porous liners can give some of the above symptoms.