Mineral, synthetic and semi-synthetic lubricating oils: can you mix it in the engine?

  When it comes to engine lubrication, one of the most classic questions that exist is: can I mix mineral, synthetic and semi-synthetic oils in my vehicle? The answer is: no . Except in emergency situations. Find more here: can you mix 0w20 and 5w20

“As soon as possible, all the lubricant should be exchanged for the one originally recommended in the vehicle manufacturer's manual, taking care to change the filter as well”, advises specialized consultant Luiz Feijó Lemos.

When we talk about maintenance of your vehicle, you can't be too careful. In this regard, correct lubrication is essential for the durability and useful life of the engine.

We must not mix lubricants from synthetic and mineral matrices in the engine at the same time, as the interaction between different oils can jeopardize the efficiency of their lubrication.

“The mixture is not recommended due to the possible incompatibility between the different chemical bases”, explains Feijó.

It is important that the vehicle owner be aware of this recommendation so that they do not seriously compromise engine parts when using or authorizing the use of different types of lubricating oil at the same time. “It can affect the operation of the oil pump and the lubrication of the piston rings and cause filter clogging, the formation of sludge and greater wear of the metal parts”, warns the consultant.

Is there a difference between mineral and synthetic oil for cars?

The answer is yes . Synthetic lubricants have characteristics far superior to mineral oils: they are more resistant to oxidation and have excellent fluidity at low temperature, the latter “a property much explored in oils with lower viscosity, such as SAE 0W-20, 5W-20, 5W- 30 and 5W-40, recommended for more modern engines”, points out Feijó. Synthetics are more durable and help more modern vehicles to perform well in daily use.

Mineral lubricants use base oils obtained by refining petroleum, which have much higher viscosities compared to synthetics, worse fluidity and greater tendency to oxidation. “They are the most common options on the market for diesel and gasoline engines. They are cheaper compared to synthetics”, says the consultant.

The semi-synthetic options are produced from blends of synthetic base oils and minerals.

Which is the best in quality?

In this case, it will depend a lot on your vehicle's engine model. The answer will always be the recommendation from the manufacturer's manual, the specifications and recommendations contained therein. It is the assembler of your car that has all the technology used in that engine to make it have the best possible performance.

If in doubt, a tip: pay attention to the viscosity standards, defined by the Society of Automotive Engineers of the United States (SAE), and performance standards, provided by the American Petroleum Institute (API) and the Association of European Automotive Manufacturers (ACEA) , in addition to the specifications of the automakers themselves. Compare this information with descriptions of oil packages available on the market.