If gasoline is the engine’s food, then oil is its bloodline. While some think its only function is to lubricate the moving parts of an engine, the role of motor oil in modern vehicles is far more complex.
Almost 20 centuries ago, the Romans used to grease the wheels of their wagons with animal fat after discovering that it dramatically improves efficiency and eliminates energy loss resulting from friction.
Only after the industrial revolution was motor oil developed to be used in steam, and later, internal combustion engines.
The contact between moving parts of an engine wears the surfaces, which leads to lower efficiency and deterioration of the engine. Therefore, no engine can work without proper lubrication. Oil creates a separating film between surfaces of internal parts of the engine, decreasing friction, wear, and production of excessive heat, thus protecting the engine.
Functioning temperatures in gasoline engines can reach up to 160°C and up to 315°C in diesel engines. The coolant used in the radiator (most often water) cannot come in direct contact with the hottest parts of the engine as oil does. This is where oil plays a critical role in cooling down the engine, by absorbing the heat from hot surfaces and taking it somewhere it can be released.
Because motor oil is so vital and in the quest for better engines, oils are engineering wonders, ameliorated by using various additives such as corrosion inhibitors, anti-wear agents, detergents and dispersants to control its viscosity at different temperatures, and improve its protecting and cooling capabilities.
But no matter how high the quality of the oil used is, there will always be microscopic particles formed from rubbing metallic parts against each other. These particles float in the engine oil and cause more and more wear, destroying the engine. This is where the oil pump and filter come in.
The oil pump moves the oil in a closed circuit, passing by the filter that removes these particles from the oil. The filter simply protects the engine by cleaning the oil. However, over time, the filter will clog up, the motor oil will thin out – saturated with these tiny metallic dirt particles. This is when you should change both to avoid burning out the engine.
Most car owners do not know when to perform this very important maintenance service. It depends on the oil and filter used. Oils can be classified into mineral motor oils and synthetic motor oils. Mineral oils are simply refined from crude oil and mixed with additives, whereas synthetic oils are man-made in laboratories, their molecules are almost all identical in size and characteristics, which guarantees better performance.
Both types of oil share the same characterization standards, composed of two numbers separated with the letter W. The first number indicates the viscosity at low temperature, the letter W stands for “winter and the second number is for viscosity at functioning temperature. The lower the viscosity it, the easier it is for the engine to pump it.
So how do you choose a motor oil for your car and when should it be changed? Taking into account that synthetic oils can be much more expensive than mineral oils, it is recommended that you use regular mineral oil for a car with little life left in, and change it along with the filter every 5,000 km.
If you plan on keeping your car for a long time, an upgrade to synthetic oil is highly recommended as it ensures better performance and protection for engines, and lasts at least twice as long as a regular mineral oil.
If you want the best performance possible, or if you really care about your car, the best oils on the market today are high performance synthetic oils.
