Mixing Synthetic & Conventional Oil

Is It Dangerous to Mix Synthetic and Conventional Motor Oil?

In short, no. It is not dangerous to mix synthetic and traditional motor oil, but we wouldn’t recommend it. Diluting the performance of synthetic oil by mixing conventional oil in with it will only detract from your engine’s ability to run ideally. Read on to learn more.

Can I mix oil types?

Synthetic lubricants continue to get more and more popular, which begs the question: can synthetics and conventional oils be mixed in a safe way?

Many are guilty of combining different types of motor oil without thinking twice in the past. Sure, the performance of the oil was likely compromised, the engine always survived—because you can safely mix synthetic and conventional oil. Believe it or not, synthetic-blend motor oil is actually this exact combination, pre-mixed for you. Unless it’s an emergency, however, we don’t recommend mixing the two on your own.

Why you shouldn’t mix synthetic and conventional oils

Regardless of its synthetic or conventional nature, all motor oil is a combination of base oils and additives. Synthetic base oils are created using a process that takes out the impurities characteristic of conventional base oils. Synthetic oils usually contain higher-quality additives, as well.

When it comes down to it, conventional and synthetic oils comprise the same elements, and they are compatible in theory. Those in the synthetic oils are simply of exceptional quality.

You can safely mix synthetic and conventional oils, but you’re not helping your engine run in a superior manner; you’re just compromising the power and performance synthetics offer on their own.

Find out how to switch from conventional oil to synthetic.

What if you have to mix oil types?

You may get yourself into a situation where you absolutely have to mix the two types of oil, like if you’re traveling. If your engine oil is low and low-quality conventional oil is the only option for you, this is safe in the short-term.

An engine that typically uses AMSOIL synthetic motor oil and is temporarily using conventional oil should be changed as soon as you are able. AMSOIL does not support extended drain intervals in which oils have been combined. If you’re already using the best possible oil, why would you want to add anything?