Oil viscosity
Viscosity characterizes the fluidity of an oil. Depending on the temperature, the oil tends to decrease in fluidity. As the temperature increases, the oil becomes more fluid. This impairs the oil's ability to adhere and resist high contact pressures. As the oil cools, it thickens, fluidity decreases, and internal friction increases. Because of this property, it is necessary to use an engine oil with a viscosity that changes as little as possible with temperature changes.
Oil fluidity is equivalent to its internal friction and is indicated by SAE units (Society of Automotive Engineers - Association of Automotive Engineers), for example SAE 30, SAE 10. A high SAE indicates that the oil is thick, a low SAE indicates a thin oil. However, the viscosity of the oil does not fully characterize the lubricating properties of the oil.
Multigrade oils
In car engines, it is preferable to use multigrade oils. They are made on the basis of liquid one-season oil (type 10W). When heated, this oil is stabilized by a so-called thickener, which ensures the appropriate lubricating properties of the oil at all temperatures. When using a multigrade oil, grades with a wide viscosity temperature range should be used, for example 10W-40, 15W-50.
Letter W (winter - winter) in the SAE designation, it characterizes the suitability of the use of oil in the winter.
Oil with enhanced lubricity
High lubricity oils are multigrade oils that, among other additives, contain substances that reduce the coefficient of friction, resulting in a 2% reduction in fuel consumption. Special raw materials are used in their production (synthetic oils). When buying such an oil, you should pay attention to the fact that this oil is approved for use by Ford.
Engine oils
Attention! Additional oil additives, regardless of their type and purpose, should not be added to the oil.
For modern engines, only HD oils should be used. HD oils are oils with enhanced lubricity, improved with a variety of additives. These additives provide better anti-corrosion protection, more favorable conditions against oxidation phenomena, the least tendency to form slags, the best viscosity change, cleaning and dissolving properties. Cleaning and dissolving additives not only reduce the formation of residues in the engine, but at the same time they have the ability to dissolve and hold these residues and all other contaminants in the engine oil in a suspended state so that when the oil is changed, these contaminants are removed along with the drained oil.
The quality of HD oils is determined by the API system (American Petroleum Institut). European manufacturers also follow this system.
The designation of the oil grade is made in two letters. The first letter characterizes the scope: S - Servise, designed for carburetor engines; C - Commercial, designed for diesel engines. The second letter identifies the grade of oil in alphabetical order.
API premium oils are SG for carbureted engines and CD for diesel engines.
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