Motor oil is the equivalent of blood for a living biological entity and the importance of this fluid is therefore not to be demonstrated, but it is essential to differentiate the functions with which it is associated. The role of engine oil includes several functions that make its use indispensable for the proper functioning of engine components.
Main functions: lubrication and protection
The main role of engine oil is to lubricate the elements present in the engine, this operation reduces recurrent friction generating heat and induces a loss of power. To do this, the oil spontaneously occupies the space between each part by dynamically sneaking in to form a film that prevents direct contact and significantly reduces the rate of wear of the components. This film will also indirectly reinforce the sealing at the cylinders and combustion chamber by the fact that the oil is a non-polar compound and therefore does not associate with other molecules such as H2O.
Engine oil also provides active protection of the metal components against corrosion, as the oil can create acids as a result of its interaction with oxygen and these can potentially damage the metal surface. It should be noted, however, that oil manufacturers have defined the chemical properties of engine oil to reduce acid formation, but the higher the temperature, the faster and more consistent the oxidation of the oil will be.
Secondary functions: cleaning and cooling
Another motor oil use is cleaning the engine. When driving a motor vehicle, the engine will not only accumulate various types of deposits, including metallic particles caused by friction. Through the creation of a film, it captures the generated particles, ranging in size from 5 to 20 microns, and concentrates them in the crankcase.
Partial engine cooling is the final role played by the engine oil, and although the coolant performs this function, it does not cool certain parts of the block. Engine oil seeping between engine parts will be able to carry away the extra heat from combustion and friction.
Choosing the right viscosity
The industrial motor oils available on the market are separated into two series whose specifications are established according to temperature. The series of motor oils containing the letter “W”, e.g. 0 W, is recommended for low temperatures and the standard series which retains excellent lubrication at high temperatures. It should be noted, however, that the engine goes through a multitude of thermal stages and a specialty oil may not be the optimum solution, in which case it is advisable to choose a multigrade motor oil that offers good performance over a variety of temperature ranges.