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The viscosity of engine oil

Vyazkotekuchest called viscosity oil. Depending on temperature, any oil changes its vyazkotekuchest. As the temperature increases, it becomes more fluid. Thus deteriorates its adhesion to metal and forming ability under a pressure of the oil film. In cold conditions, it becomes thick and viscous, plohotekuchim, the internal resistance of friction increases. This property requires the use of oils with a vyazkotekuchestyu which would change with temperature, if possible, smaller changes its properties.

When the engine is cold, it needs to be fluid enough to not to load too much work and that the starter after starting as soon as possible is supplied to the friction parts.

Viscosity or vyazkotekuchest is the same as the internal friction of the oil and is designated by the system SAE (Society of Automobile Engineers), such as SAE30, SAE10, etc. High numbers SAE indicate dense, low - into liquid oil. At the same time, the viscosity of itself does not provide conclusions about the properties of the lubricating oil.