The lubrication system of I.C. engines are closed systems, where the oil is the substance, which lubricates and cools the working parts. It also rinses out and transports all kinds of contaminants in the form of suspended solids coming out from the combustion chamber, formed during the abrasive wear of the working parts of the engine. Such contaminants are effectively trapped in filters, which are an important element of the lubricating system in any I.C. engine. However it should be noted that these filters cannot stop the oil degradation which is an irreversible chemical process and that is why, regardless of the kind of filter installed in ones car, the oil should be changed in accordance with the car manufacturer indications (including filters). The oil filters have different shapes and depending on the engine type may differ significantly regarding construction and principle of operation.