Can You Mix Different Brands Of Oil?

One question I receive in my garage from car owners is, “can you mix different brands of oil.” Surprisingly, the same question is circulating all over the Internet.

Sometimes, car owners ask whether you can mix different oil brands, viscosity, and categories. This information will be helpful if you get short of oil in the middle of nowhere. 

Whether you are stuck in an emergency or going for an affordable fuel alternative, you must take into account the key factors of the oils – weight, grade, and viscosity.

This article will answer this question and other frequently asked questions. You’ll know if you can and what happens when you mix different oil brands. 

Can You Mix Different Brands Of Oil?

Different Brands Of Oil

All API-certified oils should be compatible, and each motor oil will comprise a base compound and several additives that form the product base and other qualities that make each oil unique.

Therefore, you can safely mix one motor oil brand (e.g. Castro) with a different brand (e.g. Valvoline). You can also mix synthetic oil with conventional oil. In fact, semi-synthetic oil is a blend of fully synthetic and conventional oil.

However, oil manufacturers use different technologies and methods in oil formulation, which may eventually have different physical properties. But, as far as the oil meets API guidelines and instructions, you can safely mix them. 

However, regardless of API guidelines and compatibility, here’s my honest opinion. Mixing different oil brands means your engine will run with different anti-wear, anti-oxidation, detergents, and other additional properties. So, it won’t affect your engine in the short term but may be harmful in the long run.

Since you can mix different motor oil brands, what happens if you mix engine oils?

What Happens If You Mix Oil Brands?

Since manufacturers use several methods and technologies in oil formulation, they may not be safe to mix in the long run.

Bringing different base products, technologies, methods, and additives together may cause a clash in the engine. They may not properly mix‌, which might reduce the life of the oil.

So, will that break down your engine? No. But it could slightly lower the performance of the oil. In some cases, it may not affect the performance.

So, will it affect the overall engine performance? This depends on your engine and the brands you’re mixing. 

Mixing oils with the same SAE grade will be acceptable in most engines, and if properly mixed, you won’t have any worries.

So, if you ask, can you mix different brands of oil with the same weight? Of course, you already know the answer -You can mix them.

The grave concern should be the additives that manufacturers put for boosting performance. So, if the additives of the target oils to mix are not similar the mixing may be counter-productive leading to sludge build-up over time.

can you mix different brands of synthetic motor oil

Can You Mix Two Different Brands Of Synthetic Oil?

While we can use synthetic oils to replace mineral oil or mix it with mineral oil, is mixing synthetic oil brands bad? No, you can safely mix different synthetic brands. 

So, can you change synthetic oil brands? Most synthetic oil manufacturers state ‌it is acceptable to replace synthetic oil with another brand or mix different brands.

However, ensure you do not mix different synthetic brands with different oil viscosity. Doing so will cause engine sludge and ruin your engine.

Can You Change From Mineral Oils To Synthetic Oil? 

Using synthetic oil improves engine cleanliness and higher levels of protection without concern for compatibility or engine breakdown.

Changing to synthetic oils can also (in some cases) improve overall engine performance and even reduce fuel consumption. However, synthetic oils flow better in cold temperatures but aren’t suitable when they become too hot or in warmer temperatures as they become too thin.

Synthetic oils are engineered to perform better in all (whether cold, warmer, or extremely hot) temperatures. They’re offered in a wide range to suit all climate and weather conditions. 

Using synthetic oils means you can leave the oil longer in the engine between oil changes. The oil filter is as good as the oil itself. So, when using synthetic oil, do not forget to use a premium filter.

Always follow the manufacturer’s instructions on oil change intervals when using synthetic oils. Of course, synthetic oils should stay longer than conventional oil but don’t abuse the oil change interval.

 In all, synthetic oil is superior to mineral oils. Some applications may prefer mineral oils over synthetic oils. Therefore, I advise you to follow your owner’s manual.

Can You Mix 5w30 And 0w20?

You should be fine when you mix 0W20 and 5W20. This is because both 0 and 5 are pretty identical to work with no or slight difference in cold weather. However, the 0w will flow better at low temperature than 5w even if they have the same viscosity ratings.

The 0w is for better fuel economy. The 5w is close to it as well. You can safely interchange or mix the oils. However, it’s better to replace them than to mix them. While your engine may not experience any issues, it’s better to stick with the manufacturer’s specifications.

Is it okay to mix different oil brands or types?

Mixing different oil brands may not cause a problem in the short term, but it’s not a good idea to mix different oil brands.

Generally, premium engine oils are chemicals. So, it may not be a good idea to mix them. Do not say oil is oil. Mixing them means you’re mixing different chemicals.

However, mixing different brands of oils like Valvoline and Castro may not make any difference in the engine performance. Still, the motor oil brands may not function at their optimal level.

Final Words

In summary, I do not recommend mixing different brands of oil. Even if it has the same SAE grade, or you have Pennzoil Platinum and Ultra platinum. Sometimes, we may find ourselves in situations where there are no options.

When stocked in situations with no options, ‌mix the oils. But you have to do an oil change before the recommended interval to prevent engine breakdown.

So, when asking, can you mix different brands of oil, the short answer is that it depends on whether the oils are compatible and if the engine will accept it.

Osuagwu Solomon

Osuagwu Solomon is a seasoned automotive technician for the past 9 years, and a technical writer. He loves writing about auto professional repair guides, DIY repair guides, and buyer’s guide. After spending six years in the automotive workshop, he decided to impact his knowledge to people aside his domain, and he has achieved this by centering his Automotive writing skills on REPAIRS.

Recent Posts