The main task of auto oil is to prevent dry friction of moving engine internal parts, as well as to ensure minimum friction with maximum leakage of working cylinders.
The most important parameters of auto oil is its viscosity.
In simple language, understandable for motorist, you can say this: the viscosity of the oil is its ability to remain on the surface of the internal parts of the motor and still maintain fluidity. It seems to be not hard? But just oil viscosity varies most often depending on the temperature, was a “variable” value?
For this reason, the American Association of Automotive Engineers (SAE) a classification of motor oil viscosity is developed, which describes the viscosity of a auto oil at different operating temperatures. In fact, this classification gives the temperature range in which the engine operation is safe, provided that the manufacturer of the motor admitted to use in this engine oil with such parameters.