The range of cylinder heads is quite diverse. For passenger car engines, the cylinder head is typically a single unit—one for 3, 4, 5, or 6 cylinders—cast from aluminum alloy. In truck engines, the head can either be a single unit (for 4 or 6 cylinders) or separate, covering a group of cylinders—2 or 3. There are also individual heads, one for each cylinder. Truck engine heads are usually cast from iron.

Depending on the engine design, the cylinder head fully or partially houses the combustion chambers. Inside each head, there are intake and exhaust channels, as well as coolant passages and oil channels. The intake and exhaust channels always terminate at valve seats in the combustion chamber, and there are also mounting points for spark plugs or glow plugs and fuel injectors.

Again, depending on the engine design, each cylinder can have two, three, four, or five valves. The cylinder head may also contain valve guides, and sometimes other components of the timing system, such as camshafts, rocker shafts, pushrods, and more.

Replacing a cylinder head is necessary when the engine has overheated or suffered severe malfunctions due to faulty injectors or spark plugs. It may also be required if the cylinder head sustains significant damage from a broken valve or the entry of foreign objects into the cylinder.