Getting Up To Speed on ILSAC GF-6

ILSAC GF-6 is a direct replacement for the ILSAC GF-5 performance standard – not for the API SN PLUS service category.

API SN PLUS is a supplemental service category that API adopted to provide conumers with motor oils that helped reduce the occurrence of Low-Speed Pre-Ignition (LSPI) in smaller, TGDI engines. API just introduced a new API service category, “SP,” which is derived from ILSAC GF-6 and licensed to motor oils for gasoline engines. While API SP is backwards-compatible to previous API service categories, motor oils will still be able to be licensed as meeting the API SN PLUS, SN, SM, SL or SJ categories. API allows licensed motor oils to display the API “donut,” which indicates which API service category the motor oil meets.

Background:

ILSAC standards and API service categories are separate but interrelated. The automotive and motor oil industries work together to define a new ILSAC standard. Once the standard is appoved by ILSAC and API, API manages licensing for the ILSAC starburst, a Registered Mark that clearly identifies passenger car engine oils meeting the latest ILSAC performance standard.  

ILSAC has always tried to make its standards “evergreen,” which means they are backward-compatible. What that means is when a new standard is activated, the previous standard becomes obsolete. This latest standard meets the needs of both new and prior engine technologies. However, the new SAE 0W-16 viscosity grade has not been specified for most older engines, as most older engines are not equipped to operate with a lubricant at such a low viscosity.

For this reason, ILSAC determined the need for an ILSAC GF-6A standard, which is backward-compatible, and an ILSAC GF-6B standard, which is ONLY for SAE 0W-16. Oils meeting the GF-6B standard are NOT backward-compatible (unless specified by an OEM), and this distinction is noted clearly on motor oil labels.  

Low-Speed Pre-Ignition (LSPI) is an abnormal combustion phenomenon typically observed at low engine speeds and high loads in which the fuel/air mixture in the combustion chambers ignites before spark timing. LSPI can cause engine knock and in severe cases, catastrophic engine failure.

There are multiple theories about what causes LSPI in downsized Turbo Gasoline Direct Injection (TGDI) engines, although it is widely accepted that motor oils can play a role. Research has shown that during LSPI, a drop of oil in the cylinder may be combining with fuel droplets to create hot spots in the combustion chamber and prompting ignition before spark timing is intended to occur. Research has also shown that motor oils can be reformulated to significantly reduce their contribution to LSPI, which was the goal of the API SN PLUS supplemental service category introduced in 2018. (GM had already chosen to address LSPI with the introduction of its dexos1™ Gen 2 specification, which went into effect September 2011).

The ILSAC GF-6 standard is also designed to addresses the impact of LSPI in downsized TGDI engines.

If your car previously used ILSAC GF-5 oil, you are able to use ILSAC GF-6A specific motor oils, because they are backwards-compatible with the old specification.

For vehicles that recommend SAE 0W-16 motor oils, you can use ILSAC GF-6B specific motor oils, which are NOT backwards compatible.

To find out if a motor oil is ILSAC GF-6A compliant, the label on the bottle will have the current ILSAC starburst symbol. For ILSAC GF-6B compliant oils, look for the new ILSAC GF-6B “shield” on the labels of bottles that have SAE 0W-16 viscosity grade.