Most all-season oils are produced by a low-viscosity thickening the basis makropolimernymi additives. On the composition of base oils engine oils are divided into synthetic (prepared by chemical means), mineral (obtained by distillation of crude oil) and partly synthetic (a mixture of mineral and synthetic components). Motor oil in the engine performs multiple functions: reduces wear, friction between engine parts and protects them from corrosion, cleans, maintains a product of incomplete combustion of fuel and wear and tear, seals the clearance between the piston, its rings and cylinder, etc. Unlike synthetic oil from a mineral? The difference lies mainly in the molecular structure of the base (base) oil. In the production of synthetic oils 'built' (synthesized) molecules with predetermined, optimum performance characteristics, synthetic oils, in contrast to the mineral have a maximum thermal and chemical stability. Chemical stability means that the work of synthetic oils in the engine with them there any chemical reactions (oxidation, parafinizatsii, etc.) that would impair its performance. Thermal stability means maintaining the optimal value of oil viscosity in a wide temperature range, which means easy and safe engine start in the cold, while the maximum engine protection in its most high-zones when working at high speeds and loads. Thanks peculiarities of its molecular structure, synthetic oils have higher yield and penetrating ability. In its basic qualities of mineral oil, synthetic yields, however, it is thus much cheaper. General requirements for motor oil motor oil can be long and reliably perform their functions, providing a specified life of the engine, only strict compliance of its properties to thermal, mechanical and chemical effects that oil is a lubricating system of engine and on surfaces lubricated and cooled parts.