Learn the differences between synthetic and mineral lubricants

Repsol Lubricants

When it comes to choosing the most appropriate lubricant, knowing their origin and classification can be important when making the right decision. On the one hand, lubricants can be classified according to their state. They include: liquid, for lubricating oils, which make up the majority; semi-solid, for greases; or solid, such as graphite and even gas. Another classification can be made according to its nature, referring to the base oil it contains. In this respect, we distinguish between synthetic, semi-synthetic and mineral oils. 

When the base oil is obtained through the conventional refining of petroleum, it is considered mineral. When it is obtained through more complex processes (chemical synthesis or other), the lubricant is considered synthetic. A semi-synthetic lubricant would be the combination of mineral and synthetic base oils. 

Is it worth using synthetic oil instead of mineral oil? Synthetic bases will have a better viscosity index (viscosity variability with temperature), better cold properties (possibility of starting at low temperature), lower volatility (lower consumption), and better resistance to oxidation (lower degradation) so that, a priori, among the same quality lubricants, those formulated with synthetic bases will be better.  

In spite of this, to manufacture the lubricant, apart from the lubricant bases, additives are used that determine the fluid’s final properties. Depending on the segment we find ourselves in (motorcycle, passenger vehicle, heavy-duty vehicle, industry, etc.) and the application (engine, transmissions, etc.) there will be manufacturer-recommended regulations that we recommend complying with. In order to comply with these regulations it will be necessary to use synthetic bases for some applications and not for others. In addition, it is important to know the following warnings: 

  • It is not recommended to mix lubricants of a different nature.
  • It is recommended to always use the quality and SAE grade recommended by the manufacturer.
  • When changing from synthetic to mineral oil and vice versa, always check whether this change is permitted by the manufacturer.