Subtleties of the choice and use of engine oil
So much has already been said and written about engine oil that it has become something unrealistic to surprise or report something new. Everyone knows everything, but nevertheless, there are still a lot of questions regarding the use of oil. It was this consumable that gathered around itself so many myths like “you can not change it, but add new ones as you use it” or “it got dark - it’s time to replace it.” Let's try to understand the most controversial issues and common misconceptions.
The main characteristics of motor oils
All oils have many indicators, but the buyer should be interested in only two of them: quality (whether it will fit the car) and viscosity (whether suitable for the upcoming season). The answer to these questions is contained in the labeling, and the main ones are SAE, API, ACEA.
SAE. This marking determines the viscosity or fluidity of the oil. It is designated by one (seasonal), more often by two numbers (all-season). For example, . The number before (W) winter is the “winter” parameter, the smaller it is, the better it is to use in winter weather. The unsigned number W - summer parameter, shows the degree of preservation of density during heating. If the number is one, then the presence of the W sign indicates that the oil is winter, if not, it is summer.
*Viscosity index does not reflect the temperature at which the oil can be operated. The temperature regime indicated in the marking is important only at the time of starting the engine. The SAE index reflects the ability of the oil to maintain viscosity at certain temperatures so that the engine oil pump, at the time of start, can pump this same oil to all lubrication points of the power unit.
API. It consists of an indicator (first letter) for gasoline - (S) service and for diesel - (C) commercial engines. The letter behind each of these indicators indicates the quality level for the respective types of engines, for gasoline engines it ranges from A to J, for diesel engines - from A to F (G). The further down the alphabet from A, the better. The number 2 or 4 behind one of the designations means that the oil is intended for two- and four-stroke engines, respectively.
Universal oils have both approvals, eg SG/CD. The specification that comes first indicates a preference for use, i.e. SG / CD - “more gasoline”, CD / SG - “more diesel”. The presence of the EU letters after the API oil designation means Energy Conserving, that is, energy-saving. The Roman numeral I indicates a fuel economy of at least 1,5%; II - not less than 2,5; III - not less than 3%.
ACEA. This is a quality feature. It has three categories: A - for gasoline engines, B - for diesel engines of cars and E - for diesel engines of trucks. The number behind the category indicates the quality level. The higher the number, the more difficult the engine can operate with this oil.
Another oil is divided depending on the composition into synthetic, semi-synthetic и mineral. Minerals oxidize faster and lose their basic operating characteristics. Synthetic ones are much more resistant to temperature conditions and retain their properties for a much longer period.
The choice of the right oil for the car will largely depend primarily on the recommendations of the plant. Any car has its own internal combustion engine oil, and its characteristics will be written in the vehicle manual or on the manufacturer's website. In the same manuals, oil change intervals are prescribed, which is desirable to be changed according to the manufacturer's instructions (mostly about 10 thousand km.).
Controversial issues regarding the use of oil
If the oil has darkened, does it need to be changed immediately, regardless of the mileage traveled?
No, according to this criterion, it is certainly not worth replacing. Motor oil is a kind of mixture of a base (mineral, synthetic or semi-synthetic) and various additives that determine the performance of the lubricant. And just these additives dissolve the products of incomplete combustion of fuel, keeping the engine clean and protecting it from pollution, from which the lubricant darkens.
In this matter, you should adhere to the periods recommended by the manufacturer of your car. If for passenger cars of different brands the oil change times can be approximately the same, then for commercial vehicles, the frequency should be calculated taking into account the mode of operation.
All-weather is worse in quality?
In reality, everything is not so. Engine oil designed for operation throughout the whole year ensures a successful engine start, both in winter and in summer. Therefore, most motorists prefer this type of lubricant.
Oil can not be changed, but topped up as needed?
During operation, all sorts of deposits and soot gradually accumulate in the oil. If it is not changed, but only topped up, then all these combustion products simply will not be removed from the system. As a result, the formation of deposits will accelerate wear and significantly reduce engine life. Therefore, it is necessary not to add, but to change the oil in accordance with the manufacturer's recommendations.
This myth is justified in the case when the engine has a large wear of the piston group and it consumes a lot of oil. Then it can and should be added during the operation of the car.
You can mix if...
An unexpected situation has occurred. Example: on a long road, the oil light suddenly lit up and urgent filling is required. In this case, you will have to use the one that comes to hand.
Also, the oil can mix when switching to another type of lubricant. When changing the fluid in the motor and sump, a certain amount of old material will definitely remain, and filling in a new one will not lead to serious consequences.
Is it possible or is it possible to mix different types of oil?
When synthetic oils are mixed with semi-synthetic or mineral oils, undesirable chemical reactions can occur: the oil will simply curdle and lose its benefits. This will adversely affect the performance and durability of the engine, and will lead to its breakdown.
Experiments with mixing oils of different viscosities are conditionally allowed only if the products differ slightly in properties. Even within the line of one brand, the compositions vary greatly in characteristics. In an emergency, you can add brand material to an engine in which lubricant was previously used. But you should not mix winter and summer formulations, which are very different, for example, 20W-50.
In order not to let your car down, listen more to the recommendations of experts than to rumors and speculation. There are many prejudices, and the engine of your car is in a single copy, and it is better not to experiment on it.
