An engine cylinder head gasket is a mechanical seal that sits between the engine block and the cylinder heads in your engine. Your car uses three fluid circuits – an air/fuel mixture, a coolant, and motor oil ? to fuel, cool, and lubricate your engine. It is important that these fluids do not mix. A bad head gasket can leak fluids externally as well. If your coolant or engine oil appear to be abnormal or mixing, your exhaust smells like it’s burning coolant or oil, or you can see external leaks on the engine block itself, it’s time to change the head gasket. euromotiv sells bare head gaskets, as well as head gasket sets, designed to make the job easier and ensure the job gets done right. These gasket sets come equipped with everything you need to reseal the top end of your engine to go another 100k miles with no problems.