Engine oil
Oil is the elixir of life for the engine. Reduces friction and wear on pistons, cylinders, bearings and timing gear components. The oil seals the space between the pistons, rings and cylinder walls. As a result, the enormous pressure forces generated by the combustion process are transferred to the crankshaft almost without losses. The oil cools the engine – pistons in cylinders, crankshaft and camshaft bearings. In addition, it protects the engine against corrosion, binds dirt particles and part of the combustion residues.
Universal oils
Most of the motor oils used today are universal oils, also called multi-season, made from crude oil. So that the mineral oil can be used as engine oil, it should be enriched with various additives, which are approx 20% its chemical components. The additives protect the oil against oxidation and prevent it from foaming at high engine speeds. The most important additives are VI improvers (VI is the oil viscosity index here). They are long molecular chains, which expand with increasing temperature and contract with decreasing temperature. These additions make, that the oil adjusts to the engine temperature and maintains the correct viscosity. VI refiners, however, wear out at high temperatures and lose their properties. Such factors have an adverse effect on the durability of the engine oil, like water, fuel and combustion residues. Diluted mineral oil does not tolerate changes in pressure and temperature in the engine. Therefore, regular oil changes are not an unnecessary luxury, but an absolute necessity, if you want, to keep the engine running flawlessly.
Synthetic oils
Light oils (synthetic) they are also made of crude oil, which undergoes a complicated process, called cracking. in order to break down its molecular structure and create a new one with the use of additives. Synthetic oil is no more artificial than mineral oil, but much more expensive. In return, producers of synthetic oil promise its greater resistance, slower aging and lower oil and fuel consumption. In theory, this should mean extended oil change intervals. Unfortunately, authorized workshops do not confirm this at all. If you allow yourself the luxury of using this expensive oil, nevertheless follow the manufacturer's replacement intervals.