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Choice of motor oil
The viscosity of the oil's flow properties, which depends on the temperature. With increasing temperature, the oil becomes more fluid. This worsens the oil's ability to grip and resistance to the high contact pressure. Upon cooling, the oil thickens, its fluidity decreases and increases the internal friction. The engine must be used engine oil optimum viscosity which depends on the construction, the operation mode, the degree of wear, ambient temperature and other factors. When starting a cold engine oil should be sufficiently liquid to excessively not to overload the motor. Furthermore, after starting it should quickly reach all lubrication points.
| Fig. 2.96. The viscosity of motor oils: * 1 - the use of limited driving conditions and the environment; * 2 - not recommended for long-term operation of the crankshaft at high speed
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Oil viscosity is expressed in units - viscosity SAE (Society of Automotive Engineers - Association of Automotive Engineers USA), for example, SAE 30, SAE 10. High indicator SAE corresponds to a thick oil, low - characterizes liquid oil (Fig. 2.96). As the range of uses of neighboring SAE grades overlap, you can not pay attention to short-term temperature fluctuations. Allowed to mix oils of different viscosity grades, if you want to top-up the oil, and the ambient temperature does not correspond to the class of viscosity of oil poured into the engine. Motor oil CD, which the manufacturer designates as oil for diesel engines, are not suitable for gasoline engines. There oil application is possible in the two types of engines, in this case, the oil container both designations indicate, for example SG / CD. You can not enter into the oil supplements, regardless of their type and purpose.
A WARNING For best performance and maximum engine protection under all operating conditions, choose oils that meet the following requirements: - Classification of the API; - Viscosity of the SAE for the intended temperature range before changing the oil. Do not use motor oils that do not have signs on the vessel and SAE viscosity classification API. |
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