2.15.3. Viscosity of engine oil

Viscosity call viscosity of oil. Depending on temperature, any oil changes the viscosity. With increase in temperature it becomes more fluid. At the same time its adhesion to metal and ability of education worsens with a pressure of an oil film. On cold it becomes dense and viscous, plokhotekuchy, the internal resistance to friction increases. This property demands use of oil with such viscosity which with change of temperature, whenever possible, would change the properties less.

At the cold engine it has to be rather fluid too not to load work of a starter and that after start as soon as possible arrived to the rubbing details.

Viscosity or viscosity it the same, as internal friction of oil is also designated on the SAE system (Society of Automobile Engineers), for example SAE30, SAE10, etc. High numbers of SAE indicate on dense, low – liquid oils. At the same time, viscosity in itself does not draw the conclusion about lubricant properties of oil.