The cylinder head bolts are one of the most vital fasteners in a car engine. It is imperative that the cylinder head bolts are in excellent condition, fixed properly in position and kept well lubricated so that they can do the important job of heavy load bearing. The engine in a car is made up of several components that link and all work together to enable the car to move. The bottom block is the primary housing of the engine, known as the cylinder block including the cylinders and the components the bottom block houses, which are the pistons, connecting rods, crankshaft, and bearings. The role of the cylinder block is to provide structural support to the engine as a whole. 

The cylinder head is fixed on top of the cylinder block/bottom block, with cylinder head bolts, forming the top of the combustion chamber. Sandwiched between the cylinder head and cylinder block, acting as a sealant, is the head gasket. The cylinder head bolts have to be able to cope with extreme loads in order to maintain a secure seal between the cylinder head, head gasket and cylinder block. 

The cylinder head is comprised of a series of passages that carry the air and fuel combination needed for combustion to the cylinders; the liquid coolant, needed to keep the engine cool; and harmful fumes (produced in the engine in the process of combustion) from the exhaust  valves to the exhaust manifold and away from the vehicle.  In an air cooled engine, the cylinder head and cylinder block have fins on the outside that allows cool air, generated by a fan which is powered by the engine, to flow through the engine and keep it cool. It is imperative that the cylinder head is mounted firmly and securely to the cylinder block. The cylinder head bolts have a vital role to play in keeping the cylinder head in the right position, firmly secured and perfectly aligned.

Exposed to extremes of heat and general wear and tear, the cylinder head bolts will eventually need replacing. To keep the head gasket firmly sealed the cylinder head bolts need to be able to withstand the huge pressure exerted on them from the process of combustion, which eventually wears them down. Bearing extremely heavy loads, it is natural for the cylinder head bolt to stretch, but if the bolt stretches too far this can cause it to break. When you need to buy need cylinder head bolts, specifically designed for the make and model of your vehicle, the cylinder head bolts are the ideal replacement part.