Can You Mix 5w30 and 10w30 Oil? (Explained!)

People are mixing two different oils with two different viscosity levels. With that, people are curious if doing this can cause significant damages or not. In this article, we will explore this matter.

So can you mix 5w30 and 10w30? Yes, you can mix 5w30 and 10w30 oil, but it is not recommended.

If you mix two different oils with two different viscosities, you are doing something that is not recommended. However, many car drivers have been doing this act, and they seem to be okay. A lot of car drivers are saying that the act did nothing bad or harmful to their engines. 

Engine oil has different additives in them. These oils also have different viscosities. Therefore, mixing two oils will not blend the two oils. 

So if you want to explore this subject in your vehicle, you should know what happens if you mix 5w30 and 10w30 oil. You should know what would happen if you mix both of these oils. Engine oil helps your vehicle operate and run smoothly. 

Your engine oil will lubricate your engine and its parts to have a healthy engine and maximum performance. In addition, the motor oil will keep your engine from overheating, so motor oil is essential. With that, it only fits to explore this subject, so let us get started.

Can You Mix 5w30 and 10w30 Oil

Can I Mix 5w30 and 10w30 Oil?

So, mixing 5w30 and 10w30 oil will not cause any harm, so that you can mix the two of them. But to explain further, the 10w30 has more density compared to the 5w30. However, given their difference in density, both of these oils are very close and very similar. 

So this is why mixing the two of this oil can even be suitable for your engine. So if you are planning to mix both of these oils, you can do that. Some car drivers reported pouring over a 10w30 without even draining out the remaining 5w30. 

As a result, nothing bad happened that compromised their engine and their vehicle. But the rule of thumb is two sticks with one specific oil and one specific viscosity at a time. 

This rule will offer you a lot more benefits than mixing two different oils with two different viscosities. For example, if you mix two different motor oil, the nature is that you are mixing two oil with two different viscosities, the act will not cause any harm or failure, but it is still not recommended.

Can You Add 5w30 to 10w30 Oil?

Yes, you can top up 5w30 to your 10w30. However, if you are adding a different oil, it means the current oil is already burning. 

Therefore, there are no severe damages that will happen. In terms of operating temperature, the two oils are practically the same.

Can You Add 10w30 to 5w30 Oil?

Yes, you can also add your 10w30 to your 5w30. Of course, if you can avoid it, then you should not do it. However, if you are left with no choice, then you can add it up. There are no severe damages that can happen.

Related: 5w30 vs. 10w30 Engine Oil

Is It Ok To Mix 5w30 and 10w30 – Possible Downsides?

To simply answer, yes, it is okay to mix 5w30 and 10w30. So you can mix these two oils. But mixing different oils is never recommended, but you can do it. 

The worst situation is an engine failure, but this possibility is close to impossible. Furthermore, many car drivers have already been doing this, and they reported no damage to their vehicles for a long time.

What Happens if You Mix 5w30 and 10w30 Oil?

Some people say that mixing two different oils can cause a reduction in terms of your vehicle’s performance. They say this because they say that the additives will not blend. In addition, at low temperatures, these oils will also differ. 

The 5w30 is less thick during the cold, and it will also flow freely. But with all this, there will be no serious harm to your engine. It also does not mean that there will be no breakdown in your engine if you mix these two oils. 

The worst situation is you losing your warranty coverage over it. So you should always refer to your owner’s manual and look for any indication or warning about mixing 5w30 with a 10w30. 

Doing such a thing if the owner’s manual says otherwise can cost you your warranty coverage. It can void your warranty, and as a result, you will be charged with all the repairs to your vehicle.


In summary, mixing different oils can cause damage. However, some oils are compatible. Mixing both of these oils is never recommended, but you can do it. 

If you are left with no choice, you can mix both of them. No engine damage would happen. However, if you want to avoid mixing both of them, that would be the best, but you can also do it if the situation calls for it.



Image credits – Canva

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My name is Hank, and I've been in the automotive industry for 27 years. I've been working in my own auto repair shop for the last 13 years, and now I want to help you here, on my blog. Let me know if you have any questions. Read more