GF5 vs. GF6 Oil: Understanding the Differences

GF5 and GF6 oils are two types of engine oil standards that are commonly used in modern cars. While both standards are designed to improve fuel economy and engine performance, there are some key differences between the two.

The GF5 standard was introduced in 2010 and aimed to improve fuel economy, motor oil durability, and engine sludge protection. It was a significant improvement over the previous GF4 standard and is still widely used today. However, with the increasing demand for more efficient and powerful engines, a new standard was needed.

The GF6 standard was introduced in 2020 and is the latest engine oil standard. It is designed to enhance fuel economy and increase passenger car machine capacity. It is also backward compatible with the previous GF5 standard, which means that it can be used in older cars that were designed to use GF5 oil.

In this article, we will explain the differences between GF5 and GF6 oils and help you determine which one is right for your car.

What is GF5 Oil?

GF5 oil, or ILSAC GF-5, is a motor oil standard that defines engine oil performance requirements for use in 2011 model-year automobiles. It is an improvement over its predecessor, GF-4, and was introduced to the market in 2010. The primary goal of GF-5 is to improve fuel economy, motor oil durability, and engine sludge protection.

Here are some key characteristics of GF5 oil:

  • Improved fuel economy: GF-5 oils are designed to provide better fuel economy compared to GF-4 oils. This is achieved through the use of friction-reducing additives, as well as the ability to use lower viscosity oils without sacrificing engine protection.
  • Engine sludge protection: GF-5 oils have improved detergents and dispersants, which help to prevent the formation of engine sludge. This is important because engine sludge can cause damage to engine components and reduce overall performance.
  • Enhanced durability: GF-5 oils are designed to provide better protection against wear and tear, as well as oxidation and thermal breakdown. This helps to extend the life of the engine and reduce the need for frequent oil changes.

GF-5 oils are backward compatible with previous ILSAC standards, meaning that they can be used in older vehicles that require GF-4 or earlier oils. However, it is important to check the owner’s manual to ensure that the oil meets the manufacturer’s specifications.

Overall, GF-5 oils are a significant improvement over previous motor oil standards, providing better fuel economy, engine sludge protection, and overall durability.

GF5 vs. GF6 Oil

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What is GF6 Oil?

GF6 is the latest engine oil performance standard introduced by the International Lubricant Standardization and Approval Committee (ILSAC). It is designed to replace the previous ILSAC GF5 standard and provide better fuel economy and engine protection for modern-day engines.

GF6 motor oils are formulated with advanced technology that is best suited for today’s smaller, turbocharged, and more energy-dense gasoline direct injection engines. These oils provide several performance benefits, including enhanced fuel economy, lower emissions, and adequate deposit control.

GF6A products will display the “Starburst” API mark, and they are backward compatible, meaning they encompass GF1-5 standards as well. They are designed for SAE grades 0W-20, 5W-20, 5W-30, and 10W-30. On the other hand, ILSAC GF6B includes all the requirements of GF6A, but it is only used for SAE 0W-16 grades.

Automakers are the driving force behind ILSAC GF6, and they have worked closely with oil manufacturers to ensure that GF6 oils meet the latest engine performance and protection requirements. The Castrol engine oil portfolio has upgraded and is compliant against the GF6 standard.

It’s safe to say that, GF6 oil is an essential upgrade for modern-day engines, providing better fuel economy, lower emissions, and adequate deposit control. It is designed to meet the latest engine performance and protection requirements and is backward compatible with previous ILSAC standards.

Differences Between GF5 and GF6 Oil


One of the biggest differences between GF5 and GF6 oils is their viscosity. GF6 oils are typically thinner, with a lower viscosity grade, than GF5 oils. This is because GF6 oils are designed to reduce friction and improve fuel economy, which requires a thinner oil that can flow more easily through the engine.

Friction Reduction

GF6 oils are designed to reduce friction between engine components, which can help improve fuel economy and reduce wear on the engine. This is accomplished through the use of advanced additives and base oils that provide better lubrication and reduce engine friction.

Fuel Economy

GF6 oils are specifically designed to improve fuel economy, which is becoming increasingly important as automakers strive to meet more stringent fuel efficiency standards. By reducing engine friction and improving lubrication, GF6 oils can help improve fuel economy by up to 3%.

Engine Protection

GF6 oils provide better engine protection than GF5 oils, thanks to their advanced additive packages and improved base oils. This helps reduce engine wear and extend the life of the engine, which can save drivers money on repairs and maintenance over the long term.

As you can see, GF6 oils offer a number of advantages over GF5 oils, including improved fuel economy, better engine protection, and reduced friction. While GF6 oils may be more expensive than GF5 oils, the benefits they provide can be well worth the extra cost.

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Which One Should You Choose?

When it comes to choosing between GF5 and GF6 oil, it ultimately depends on the make and model of your vehicle. GF6 is the newer industry standard, designed for today’s smaller, turbocharged, more energy-dense gasoline direct injection engines. On the other hand, GF5 is still a reliable option for older vehicles that do not require the higher performance benefits of GF6.

It’s important to note that GF6 is divided into two separate sub-categories: GF6A and GF6B. GF6A is fully backward-compatible for older vehicles that previously used GF5 oils, while GF6B covers the new, lower-viscosity oil grade OW-16 and will not be backward-compatible in most cases (unless specified by the OEM).

If you have a newer vehicle that requires GF6, it’s important to make sure you are using the correct sub-category for your engine. Using the wrong sub-category could potentially cause damage to your engine and void your warranty.

With that said, it’s best to consult your vehicle’s owner manual or speak with a trusted mechanic to determine which oil grade is best for your specific make and model. They can provide expert advice on the best oil to keep your engine running smoothly and efficiently.