Understanding ILSAC ratings for Automotive Lubricants
Originally published in July 2023, when GF-6 was the current ILSAC specification, this guide has been updated to include GF-7 and explain how the different categories affect oil selection.
When choosing engine oil, you may see an ILSAC specification alongside its viscosity grade and API rating. These markings help identify the oil’s performance, but they describe different aspects of its suitability.
ILSAC standards combine petrol engine protection with fuel-economy requirements. Understanding them can help you choose the right lubricant without assuming that every newer specification suits every vehicle.
What is ILSAC?
ILSAC represents a joint effort by American and Japanese vehicle manufacturers to establish passenger-car petrol engine oil performance requirements.
Its standards address the demands manufacturers place on lubricants, including engine protection, fuel efficiency and emissions-system compatibility.
API—the American Petroleum Institute—operates the Engine Oil Licensing and Certification System. Through this voluntary programme, qualifying oils can be licensed to display recognised API quality marks.
ILSAC therefore helps define performance requirements, while API administers the licensing system associated with those marks.
What does an ILSAC specification tell you?
ILSAC specifications use the letters GF, followed by a generation number and, for more recent standards, an A or B suffix.
Each generation sets requirements covering engine tests and the oil’s chemical and physical properties. The standards are closely related to API petrol engine oil categories, but include additional requirements, particularly for fuel economy.
They also apply to specific viscosity grades. An API rating alone does not automatically establish that an oil meets an ILSAC specification.
How have ILSAC standards developed?
Successive generations have responded to changing engine designs and operating demands.
| Specification | Its place in the sequence |
|---|---|
| GF-1 to GF-4 | Earlier generations that progressively developed engine protection and fuel-economy requirements. These are now obsolete. |
| GF-5 | Introduced in 2010, with developments in deposit protection, fuel economy, emissions-system compatibility and protection when using ethanol-containing fuels. |
| GF-6A and GF-6B | Introduced in 2020, adding requirements addressing low-speed pre-ignition and timing-chain wear, alongside other performance improvements. |
| GF-7A and GF-7B | Introduced in 2025, building on GF-6 with further engine-protection and efficiency requirements. These are the current generations. |
GF-5 and GF-6 may still appear in vehicle handbooks and older product literature. That makes understanding their replacement routes useful when selecting oil today.
What is the difference between GF-7A and GF-7B?
GF-7A covers qualifying oils in SAE 0W-20, 5W-20, 0W-30, 5W-30 and 10W-30 grades. It provides a replacement route for GF-6A, GF-5 and earlier ILSAC specifications, while retaining the vehicle’s required viscosity and any additional manufacturer requirements.
GF-7B applies specifically to SAE 0W-16 oils and replaces GF-6B for appropriate applications.
The B designation does not mean the oil is universally better. It identifies a different viscosity application. Do not substitute a GF-7B 0W-16 oil for a GF-7A oil unless the vehicle manufacturer permits that grade.
Why does low-speed pre-ignition protection matter?
Low-speed pre-ignition, usually shortened to LSPI, is abnormal combustion that occurs before the spark plug is intended to ignite the mixture. It can affect some turbocharged, direct-injection petrol engines and may cause severe damage.
GF-6 introduced a specific LSPI protection requirement. GF-7 develops this further by assessing protection with aged oil as well as fresh oil, helping address performance throughout the oil’s service interval.
GF-7 also tightens requirements in areas including timing-chain wear, piston cleanliness and fuel economy. These developments respond to the combined demands of efficient operation and engine durability.
Which marks should you look for?
For appropriately licensed products:
- The API Starburst identifies oils meeting the current ILSAC GF-7A requirements.
- The API Shield identifies oils meeting ILSAC GF-7B, specifically in SAE 0W-16.
- The API Donut shows the licensed API service category, viscosity grade and, where applicable, Resource Conserving designation.
The relevant API petrol engine category is SQ. However, an SQ claim by itself does not establish that every oil also meets GF-7A or GF-7B. Check the individual product’s stated specifications.
Choosing the right oil for your vehicle
Start with the handbook’s viscosity and performance requirements. If it specifies an older ILSAC standard, check the appropriate replacement route rather than choosing solely by the highest number.
Also check any manufacturer-specific requirements. ILSAC is a petrol engine oil standard; it does not replace diesel specifications or every additional approval a vehicle may require.
Explore Rock Oil’s automotive lubricant range, or contact our technical team for help matching a product to your vehicle.