Tthe BMW Cylinder Head Gasket's ability to seal not only the coolant channels in the head, but also the oil and compression chamber, is unique of all the gaskets and seals on your vehicle.
Every time the engine heats up the cylinder heads and the motor block expand. The cylinder head gasket set is designed to not only compensate for this expansion, but also withstand this stress and still keep the different areas in this part of the engine separated from one another. In time they have been known to fail on a BMW.
When the BMW cylinder head gasket set fails, it can occur in a number of different ways. The most common is when the section that separates the coolant channel for the combustion chamber is breached. The owner of the BMW will become aware of the breach in their cylinder head gasket set when white smoke is coming from their tail pipe when the engine is running. The white smoke is actually steam from the vaporization of the water in the coolant that has entered the combustion chamber and is heated past the boiling temperature.
If blue smoke is coming from the tail pipe, this is the burning of oil in the combustion chamber and again a breach in the cylinder head gasket set has formed. The final type of failure of the cylinder head gasket set is when coolant is in the crankcase. This is when there is a breach between the oil and coolant galleys in this joint.
If any of these conditions is found on your BMW, the head gasket will have to be replaced or permanent damage will be caused to your engine.