Updated at: 15-03-2022 - By: micdot

Many car owners have been unsure if a 15w40 oil and a 10w30 oil mixture is the best option for their vehicles. Some car owners might claim it’s fine, but others would argue that it isn’t acceptable. This article is for those who are interested in learning more about this topic. So, is it possible to combine a 15w40 oil with a 10w30 oil in a single mixture? Yes, it is correct. There’s no harm in mixing a 15w40 with a 10w30 oil, but it’s not a good idea, as you won’t get the full benefits of each oil. Some automobile owners are put off by the idea of blending two different motor oils in terms of viscosity and weight because they wish to avoid encountering harmful dangers. Some car owners, on the other hand, wonder why so many people are combining 15w40 oil with 10w30 oil. As a result, we will now discuss the effects of combining 15w40 and 10w30 motor oils.

What happens if you mix 15w40 oil with 10w30 oil?

That and other questions will be addressed in this post. As a result, we can now begin.

Can I Mix 15w40 and 10w30 Oil?

If you wish to, you can blend a 15w40 oil with a 10w30 oil. In the event that you do not like to combine them, you can do so as well. It all comes down to who owns the automobile, and that’s the crux of it. There are no regulations or restrictions on this, however there are some guidelines. For instance, it is not suggested that you blend two different oils of varying viscosity and weight. However, as previously said, if you like, you can blend a 15w40 oil with a 10w30 oil.

The two motor oils can be mixed, but only if they come from the same manufacturer. Alternatively, if you’re stuck with a choice between the two, you can combine them. If you’re out of the scenario, you can always perform an oil change.

Can You Add 15w40 to 10w30 Oil?

A 15w40 oil may be added to a 10w30 oil. You are free to include it if you so desire. There are no regulations that indicate you can’t mix a 15w40 oil with a 10w30 oil if you’re low on oil and there’s no other oil available that’s the same as your present oil.

Can You Add 10w30 to 15w40 Oil?

Your 15w40 oil is compatible with 10w30. Other customers have experienced no damage to their vehicles after using it in place of their regular oil. In other words, you may simply add it up and be good to go.

Is It Ok To Mix 15w40 and 10w30 – Possible Downsides?

A 15w40 oil can be mixed with a 10w30 oil. Doing so is a common practice among car owners. Vehicle damage hasn’t been noted to be an issue for them. Even though mixing a 15w40 oil with a 10w30 oil is not suggested, some motorists continue to do so. The reason for this is that their engine has never failed or their performance has not changed.

An issue you may run into is with your vehicle’s warranty. You could lose your guarantee if you mix 15w40 oil with 10w30 oil, for example.

What Happens if You Mix 15w40 and 10w30 Oil?

No harm will be done if you mix 15W40 and 10W30 oils together. Numerous motorists have already used a 15w40/10w30 oil blend without experiencing any problems. They claimed that their vehicle had not undergone any alterations. Despite the fact that it won’t hurt your engine, combining 15w40 and 10w30 motor oils won’t do you any good. To your car, there are no new features.


People have been debating whether 15w40 and 10w30 oils can be mixed. Some people are already doing it, while others are concerned about the implications. While 15w40 oil can cause engine failure when mixed with 10w30 oil, there are no serious consequences if you combine the two oils. As a result, while mixing the two is technically possible, it is not advised.