Motor oils - how to choose

Filling with the wrong engine oil can cause serious damage to the power unit. To avoid high repair costs, it is worth choosing the right oil.

The first and only rule of thumb should be to follow the engine manufacturer's recommendations. Modern power units are mechanisms made using the latest technologies and their design in terms of parameters strictly complies fate. Therefore, modern engine oil is a structural element of the engine and therefore must be consistent with all its elements in terms of mechanical, chemical and thermal resistance.

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Most of the oils in use today are synthetic oils, which provide much better protection and cooling for moving engine parts than mineral oils. They also have a greater ability to disintegrate particulate matter resulting from the combustion process, which are more easily captured by filtration systems.

The most important and advantageous feature compared to mineral oils is the low viscosity of synthetic oils, which allows accurate oil coverage of surfaces subjected to friction in almost any temperature range, especially at low temperatures, when every engine oil thickens.

Do not mix synthetic oil with mineral oil, and if so, with semi-synthetic.

Also, do not use synthetic oils for engines of older cars with high mileage, previously operated with mineral oil. Filled synthetic oil can in this case cause great harm, because the detergents and cleaning components included in its composition will dissolve the accumulated dirt and deposits that contaminate engine components. In addition, most older engine seals were made from rubber formulations not designed to work with synthetic oil formulations. Hence the high probability of oil leakage.

Finally, it is also worth following the rule to use oils from well-known and recognized manufacturers, even though their purchase price may be higher than others.

Years of experience always pay off with the quality of the product, which, in the case of engine oil, determines the performance and service life of our car's engine.

According to accepted SAE standards, oil viscosity is indicated by numbers from 0 to 60, and the 6-point scale “W” (winter) from 0W to 25W determines the temperature at which the viscosity changes so much that the oil thickens to such a state when starting the engine becomes impossible.

In practice, it's like this:

– for viscosity grade 0W, this temperature ranges from – 30°С to – 35°С,

- 5W - 25 to - 30 ° C,

- 10W - 20 to - 25 ° C,

- 15W - 15 ° C to - 20 ° C,

- 20W - 10 ° C to - 15 ° C,

- 25 W - from -10 ° C to 0 ° C.

The second segment of the scale (5-point scale, 20, 30, 40, 50 and 60) determines the "strength of the oil", that is, the preservation of all properties in the high temperature range, i.e. 100°C and 150°C.

The viscosity index of synthetic motor oils ranges from 0W to 10W, and often 10W oils are also produced as semi-synthetic. Oils labeled 15W and above are usually mineral oils.

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All these markings can be found on the packaging of each engine oil, but their analysis does not answer the question - is it possible to mix oils, and if so, which ones?

Of course, nothing bad will happen to the engine if, while maintaining the same quality parameters and viscosity class, we change the brand - that is, the manufacturer. After driving a significant number of kilometers, it is also possible to use oil of a slightly higher viscosity grade, i.e. denser. It will seal the engine better, improving its condition a little, although you should know that it will not repair a worn engine.

Examples of engine oil prices

Oil type motor / brand	Oil type	Online shopping supermarkets e.g. Selgros zł / liter	Buying at stations gasoline PKN orlen zł / liter
Mineral oil Castrol Platinum мобильный shell	15W / 40 Magnatec 15W/40 Classic 15W / 40 SuperM 15W50 high mileage	27,44 18,99 18,00 23,77	36,99 17,99 31,99 not sold
Semi-synthetic oil Castrol Platinum мобильный shell	10W / 40 Magnatec 10W/40 10W / 40 SuperS 10W / 40 Racing	33,90 21,34 24,88 53,67	21,99 42,99 44,99 not sold
Synthetic oil Castrol Platinum мобильный shell	5W / 30 Edge 5W40 OW / 40 SuperSyn 5W / 40 Helix Ultra	56,00 24,02 43,66 43,30	59,99 59,99 (OS/40) 59,99 not sold