To ensure engine parts are properly lubricated, the oil level must be within the normal range. If it drops below the MIN mark, it should be replenished as soon as possible. Ideally, you should use the same oil as what is currently in the engine. But what if you don't have it on hand? Is it allowed to use a different type? Can oils from different manufacturers and brands be mixed? Let us explain.
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What is motor oil made of?
To understand which oils can be mixed and which cannot, you
need to know their composition. Without delving into chemistry, there are two
main components of modern motor oil:
- Base oil (or just base). It can be either mineral or synthetic. There are also semi-synthetic options, which are essentially a mix of the first two types. Synthetic oils are made from a complex mixture of hydrocarbons, while mineral oils are obtained through direct distillation of crude oil. The former is considered more stable and higher quality, while the latter is significantly cheaper.
- Additive package. Each lubricant manufacturer has its own. Additives are needed to provide the motor oil with the necessary properties. For example, resistance to oxidation, protection of parts from corrosion, or preventing the oil from foaming, and so on.
We have dedicated separate articles to the types of automotive oils and how to choose the right oil for a specific car.
Can you add different oil to the engine?
This is about a situation where the lubrication level has dropped below the minimum, and you don't have the same oil on hand. Ideally, you would want to purchase the same oil that's already in the engine. But let's imagine you find yourself far from good auto shops. This can happen during long road trips, and the nearest shop or service station offers a completely different lubricant. So, is it possible to mix oils from different manufacturers?
If this could have catastrophic consequences for the engine, mixing different oils would be prohibited. However, there is no strict prohibition. There are only recommendations not to mix products from different brands. Why is that?
The additive package is a whole complex of chemical substances. Of course, before using them in their oil, manufacturers test the components for compatibility. However, no one can guarantee that these substances won't react with the additives in other oils. The result of such a reaction could be, for example, the formation of sediment. Or simply a change in properties, which is also undesirable. So is it worth the risk? What happens if you mix oil in the engine with another type?
As we've noted, the risks of serious consequences are small. If you add about ten percent of the total volume (for example, 400 ml when replacing 4 liters), the properties of the oil are unlikely to change significantly. In any case, adding oil, even from another manufacturer, is better than continuing the trip with an insufficient amount. By the way, when replacing oil, some old lubricant remains in the system. Typically, this is about 400-500 ml, which doesn't cause any harm if you suddenly switch to a different manufacturer's oil.
Sometimes, in older engines, a lot of oil is "burned off." In this case, you may need to add more than 10%. Which oil should you use? If possible, use the same manufacturer and the same base. If not available, any other oil suitable for your car type will do. So, the answer to whether you can mix motor oil from different manufacturers is simple: it's not advisable, but in critical situations, it's permissible.
What you definitely should not do is add lubricant intended for transmission units to the engine, even if they look similar externally and the transmission oil label indicates the same base: mineral or synthetic.
Can you mix oils with different viscosities?
This is simpler. A "mix" of oils with different viscosities might only exhibit unusual viscosity-temperature characteristics. If you're not currently operating the vehicle under near-extreme conditions (e.g., in extreme cold or heat) and the volume you topped up was no more than 10%, there's no need to worry. Had to add more? In that case, it's better to replace the oil with a new one if possible. Especially if you have a modern turbocharged engine, which is very demanding regarding the quality and viscosity of the lubricant. You can perform the oil change yourself: we have a detailed guide. So, if you're unsure whether you can top up the engine with a different oil that has a different viscosity, don't worry—you can if it's a small amount.
So, in brief:
- If the oil level drops below the minimum, it needs to be replenished (add more oil).
- Ideally, you should use the same oil as what is currently in the engine.
- If you can't find the same oil, try to use oil from the same manufacturer and with the same base.
- Adding up to 10% of the total oil volume will not affect its characteristics—you can continue to use the car.
- If you had to add more, it's best to change the oil to new when possible. Of course, include replacing the filter as well.{alertSuccess}