Can You Mix Different Brands Of Synthetic Motor Oil?

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Motor oil is one of the critical lubricants for your car. All the motor oils have a similar Physical appearance. Therefore, one of the questions that come to your mind is, can you mix different brands of synthetic motor oil? Although they all seem the same, there are some differences between the motor oil.

You must use the correct oil for long-lasting and better performance of your engine and improve fuel economy. The motor oil you use must comply with the car manufacturer’s specifications.

There are many arguments for mixing different brands of engine oil. In this article, I’ll explain: can you mix two different brands of synthetic oil? Is it safe to mix different viscosity motor oils (weight)? And much more information about engine oil mixing.

Mixing different engine oil brands.
Mixing different brands of synthetic oils.

What are synthetic motor oils?

Synthetic motor oils are chemically developed petroleum components as a base stock. This chemical process removes the impurities inherent in petroleum oils; therefore, this oil has a more advanced base stock.

The unique characteristics of synthetic motor oils.

  • Synthetic motor oils have identical molecules, though petroleum base oils have uneven size molecules. Due to this molecule’s size, synthetic oils are slowly thinning at higher temperatures than conventional motor oils. Moreover, it flows easily at extremely low temperatures. So synthetic motor oils give better protection in lower and higher temperatures.
  • Synthetic oils remove petroleum oil’s impurities, such as sulfur and wax.


Can You Mix Different Brands Of Synthetic Motor Oil?

Yes, you can mix different brands of synthetic motor oils if the two oils have the same API certification and SAE viscosity grade. But mixing two different oils is not the best practice; barring an emergency, it is acceptable. It neither improves performance nor damages the engine. After mixing, it creates a new type of lubricant, which is not the same as the previous two oils. However, topping up engine oil with different brands is not a big problem. 

Different lubricant manufacturers use various technologies to make these oils. Therefore different brands of synthetic motor oils have different levels of chemical additives packages to enhance performance, efficiency, and protection. Therefore continuous mixing and use of motor oil brands can cause some performance problems in the long run.

We recommend always following your vehicle manufacturer’s recommended oil grade and brand for optimum performance.


Are All Synthetic Oils The Same?

No. All synthetic oils are not the same. Different motor oil manufacturers use various techniques to formulate synthetic oils, and therefore same API service category and SAE-grade synthetic motor oils are not the same. There can be minor additives or base oil differences, and even a more minor additive can make significant changes.


Can You Mix Different Viscosity Grades of Synthetic Motor Oils?

No. You should not mix different viscosity grades of synthetic motor oils together. Different grades of motor oils, like mixing 5W30 with 5W20, are not recommended. These two oil grades have different additives, like viscosity improver (VI). So mixing different grades can create slugs on the engine in the long run.


Can I Mix Different API Classes Oils?

No. You should not mix different API classes of motor oils. Different API classifications are developed using different additive mixing ratios; therefore, the same motor oil manufacturer’s different API grades are not the same. This can build engine slugs in the long run.


Can You Mix Synthetic And Conventional Oil?

Yes. You mix synthetic and conventional oil if both have the same SAE grade and API classification. However, after mixing, it does not give full synthetic oil performance. Therefore always use a single oil type; in an emergency, it is ok to mix motor oils.

Synthetic oils have excellent performance in higher temperatures than conventional motor oils. Because synthetic oils have identical molecules and conventional oils have uneven molecules. Therefore when temperature increases, synthetic oils are slowly thin than conventional oils.


Which Synthetic Motor Oils Are Safe to Mix?

You can mix motor oil brands if the two oils use the same API certification and SAE grade. However, we are not recommended to use mixed oils in the long run. If the two oils do not satisfy the following requirements, mixing is not safe.

  • If the base oils are identical, but the performance-boosting additives are different (type and/or quantity), it is also not the perfect mix.
    It is not a perfect mix of the two motor oils’ base stocks are different but have identical performance-enhancing additives (type and/or quantity).
  • The easiest and most reliable way is to use the oil brand recommended by the car manufacturer or an equivalent brand that meets the car manufacturer’s requirements.


Can You Mix Full Synthetic Oil With Synthetic Blend Oil?

Yes. You can mix full synthetic oil with synthetic blend motor oils. The synthetic blend combination of conventional motor oil with synthetic base stocks. After mixing these two types of engine oils, it may not give the original synthetic oil performance and protection. Because synthetic blend oil already contains petroleum base stock.


What Happens If You Mix Engine Oil?

Mixing engine oil does not cause any problems in the short run. However, if you continuously use mixed engine oil, it can form slugs on the engine. If your vehicle manufacturer recommends using only synthetic motor oils, never use regular petrol, as it will increase the moving metal parts’ wear and shear.


Final Word.

The engine is the most critical component of a vehicle and requires the proper motor oil to lubricate the engine’s moving metal parts. As a result, when selecting motor oil, you must be extremely careful. There are several motor oil classifications.

Can you mix two different brands of synthetic oil? The straightforward answer is yes. However, mixing different synthetic motor oils is not recommended. Mixing different synthetic oil brands is acceptable as long as the SAE viscosity grades and API service category are the same.

However, there may be differences in additive use to improve performance. Because of the difference in additive components, there may be slight performance differences in the long run when mixing two different oil brands. So at your next motor oil change, use only one type recommended by your vehicle manufacturer.

Furthermore, mixing different grades of synthetic motor oil is not advised. When different viscosity grade oils are mixed, deposits and slugs can form on the crankcase.

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