Can You Mix 5w30 and 10w30 Oil? (My Best Guide)

The viscosity and application of the two engine oils, 5w30 and 10w30, differ. And knowing the difference between them often helps us to choose the best lubricant for our car.

But, can you mix 5w30 and 10w30 oil together?

Although it is not a good idea to mix two different oils, many drivers do so without experiencing any engine damage. Hence, mixing 5W-30 and 10W-30 engine oils is also possible, but it’s not always recommended.

Due to their distinctive weights, these two oils flow at varying rates, but this discrepancy isn’t great enough to harm your engine.

Well, if you’re still confused, don’t worry! Stay with us till the end as we have covered everything in this article.

Can You Mix 5w30 and 10w30 Oil


Can You Mix 5w30 and 10w30 Oil?

Yes, you can mix 5w30 and 10w30 without a second thought. This is because they essentially have the same viscosity at the same temperature, making them blend nicely together for your car. Therefore, we can assure you that combining them is safe and won’t result in any significant engine issues.

Even though 10w30 and 5w30 have similar viscosities and can work well together, you should know that 10w30 is denser. Therefore, it would be preferable if you continue using the motor oil suited for your engine.

Further, you should always remember that the viscosity at high temperatures will alter when operating at colder temperatures, even though they have the same weight. This is why oil types with thinner viscosities tend to flow to the top ends.

Also Read: Can You Mix 5W-20 and 5W-30?

Difference between 5w30 and 10w30

As the gasoline in 5w30 is thinner and can reach the smallest areas of the engine, it is less dense and more efficient than 10w30.

Well, a viscosity engine oil specially used for engine lubrication is 5w30. Its viscosity is represented by the number 5, with 1 being the least viscous and, hence, the most efficient. They can withstand various temperatures for various vehicles and have low viscosity.

Difference between 5w30 and 10w30

On the other hand, the viscosity of engine oil for lubrication that has been identified and certified by SEA is 10w30. As indicated by the number 10, this viscosity is higher than 5w30. Therefore, it is a denser fuel that operates over a narrower temperature range.

Compared to 10w30, 5w30 provides superior lubrication, which is why it is better suited to commercial vehicles and cars with heavy load engines. Comparatively, 5w30 is best for individual vehicles that use light-duty diesel and gasoline engines.

Both 5w30 and 10w30 are multi-grade, but 10w30 is enough if you live near the mountains. Hence, 5w30 performs significantly better in the cold. However, if we talk about hot summers, 10w30 will still flow well.

What is The Right Way to Mix 5w30 and 10w30 Oil?

The strategy is to pour the light oil into the engine while combining two oils of various weights. Therefore, 5w30 should be poured first. The heavier oil, 10w30, should be added after the light oils are on top.

Well, the motor oils can be appropriately blended in this manner.

What is The Right Way to Mix 5w30 and 10w30 Oil

Caution, the combination of synthetic and conventional oils is something that you should never do. Moreover, it is also crucial to weigh the engine oils you plan to add. Well, you should proceed only if they are close in weight so that they can operate at the same speed.

When determining its proper weight, weather is also crucial to avoid damaging the engine.

Pros and Cons of Mixing 5w30 and 10w30?

Due to their identical SAE ratings, both 5w30 and 10w30 engine oils function effectively at high or operating temperatures. In colder regions, 5w30 works great, whereas 10w30 is a perfect choice for summertime.

Therefore, mixing them will make your engine run flawlessly at both temperatures.

The combination of 10w30 and 5w30 won’t harm your car, but it will also not let you experience all of the advantages of 5w30. Since the 10w30 has a higher density than the 5w30, you won’t obtain the desired results.

Due to their differing grades, 5w30 is meant for light usage because it is more lightweight and the density is lower. On the other hand, 10w30 is of better grade with more density and is ideal for more powerful engines.

Hence, using their mixture for a prolonged period may cause severe harm to your engines.

What happens if you mix different oil weights?

It is generally not advised to blend oils of different weights. However, different viscosity grades are compatible and mixable if they fall under the same motor oil brand. Doing so will result in a different viscosity from the original oil in the engine.

At first, the mixture may appear to be working perfectly in your engine. However, in the long run, this would not be the same case.

Advice for Mixing Different Oil Weights

When combining two distinctive oils, an oil additive is frequently used. First, the additive will hasten the movement of the heavier oil in the system, and the lighter one might be compatible with it. Also, utilizing the additive has the additional benefit of reducing engine wear and tear.

Advice for Mixing Different Oil Weights

Since most additives are made of synthetic materials, they work to safeguard the engine over time while enhancing its smooth operation. Hence, when adding an oil additive, remember to pick the appropriate one for the grade of oil you’ll be using.

When combining two different types, there are a few guidelines to follow

  1. When mixing, you must be certain of the weight of the oil and ensure that it is comparable. Your engine won’t operate as smoothly as it should if you combine oils with a significant weight difference.
  2. After you are done with mixing, don’t forget to check its level. Look at the level first if you notice there isn’t enough oil weight in the tank before starting your car immediately. It would be beneficial if you chose the manual’s suggested level.

Avoid letting the oil spill when combining the motor oils since your car’s vents may begin to smell like burning oil.

Further, consider taking assistance from a mechanic if you are still worried about something. He will know how to blend them correctly in a secure manner.

Frequently Asked Questions (FAQs)

Is it OK to use 10w30 instead of 5W-30?

It is entirely acceptable to substitute 10w30 for 5W30. This is so that both the oils, 5W-30 and 10W-30, will function equally and have the same viscosity (SAE 30) when the engine runs.

 Which is better: 5W-30 or 10w30?

Diesel and Light Duty petrol engines found in private vehicles work best with 5W-30 multi-grade oil. Additionally, compared to 10W-30 oil, it offers a superior cold temperature start.

Contrastingly, commercial cars and cars with heavy-load engines benefit more from the slightly thicker oil, 10W-30, because it offers greater lubrication.

Therefore, it’s important to consider where you will be operating the automobile before buying engine oil to determine which is preferable

Is 10w30 thicker than 5w30?

Although at 100 degrees Celsius, both oils have a similar viscosity, 10w30 is thicker than 5w30. Hence, 10w30 oil will flow well at high temperatures due to the narrower temperature range, whereas 5w30 oil will flow successfully at low temperatures.

Is 10w30 good for high mileage?

10W-30 motor oil is a pretty good oil for longer mileage. It enhances fuel efficiency while allowing older engines to consume less oil. This is so that oil leaks, sludge, and deposits won’t occur in older engines having a mileage of above 75000, where thicker oil is required to properly maintain the crucial element of the engine.

What happens if I put 10W 30 instead of 5w 20?

Most likely, just a few differences are noticeable when 10w30 is used instead of 5w20, especially if the engine is old and worn out. Well, the ability to ignite quickly, a benefit of using thinner oil, would be missing in this case. Moreover, uneven oil circulation due to the use of 10w30 around the piston may shorten the life of an engine.

Is 10W30 better for summer?

Yes, 10w30 is better for summer. As it uses a thicker oil instead of 5W30, it will provide the most protection in the summer. Moreover, due to the heat’s influence on the oil’s thinning, engines require heavier oil at this time.

Is 5W30 good for summer?

With a wide viscosity range, 5w30 can lubricate, seal, and safeguard an engine’s internal parts in every climatic situation. Therefore, its ability to perform well in both the summer and the winter prevents you from changing oils repeatedly.


Although you can blend the two oils, you should be aware that mixing motor oils is not advised as it offers no specific benefits. Additionally, this behavior may void the warranty protection offered by the maker of your car.

Well, we’d suggest you store more of the oil that is ideally suited for your car. So, if an emergency arises, topping off the oil and continuing to drive won’t be a problem.

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