Formerly a simple cover, today a multifunctional component: cylinder head covers not only seal the engine, they can do much more.
If it is dripping at the bottom, it may be coming from the top: Defects in the cylinder head cover become noticeable through leaks. And this is usually a result of the natural ageing of the material, even if they are usually made of highly stable thermoplastic or a combination of thermoplastic and aluminum.
Vibrations and large temperature fluctuations cause the plastic to fatigue. However, tightening the screws too tightly can also lead to warping or breakage/cracking of the component, as can mechanical damage following an accident.
Cylinder head covers can do a lot: Modern designs integrate additional components such as oil mist separators, pressure control valves, non-return valves or vacuum reservoirs. But they also take on additional functions such as the attachment of ignition cables and fuel lines, the wiring harness and the oil filler pipe. This integration in a single assembly makes cylinder head covers a technically and geometrically complex product.
MAHLE has developed a new product range that also covers cylinder head covers: