ILSAC GF-7: Implementation “tentatively” planned for Q2 2028

The latest ILSAC passenger car engine oil specifications, GF-6A and 6B, were introduced in May 2020 to ensure oils continue to meet the needs of newer vehicles. A draft of improvements to engine oils included greater protection against low-speed pre-ignition (LSPI), better fuel economy, enhanced emission control system protection, more stringent sludge and varnish control and improved high-temperature deposit protection of pistons and turbochargers. 

A request for the next ILSAC engine oil performance standard, GF-7, has not yet formally been issued. Nevertheless, work is underway to progress the category alongside advancements in engine technology. On June 29, 2022, a laundry list of potential updates to ILSAC GF-6 was reviewed during a meeting of the American Petroleum Institute’s (API) Lubricant Standards Group in Seattle, Washington, U.S.A.

Following opening remarks by outgoing Lubricants Standards Group (LSG) Chair, Mike Alessi, and incoming Chair Darryl Purificati, Ford Motor Co.’s Michael Deegan, chairman of ILSAC, gave a presentation on Emergent Specifications for Passenger Car Engine Oils which included the ILSAC GF-7 requirements. 

The new performance category will feature improvements to the Sequence IIIH engine test that measures lubricant thickening and piston deposits under high-temperature conditions. A 10% merit increase in average weighted piston deposits (AWPD) from the current 4.2 minimum pass limit to 4.6 was outlined, as well as a reduction in mini-rotary viscometer (MRV) viscosity from 60,000 to less than 40,000 centistokes (cSt).

Deegan defined the need for new Sequence V and VI engine test platforms. The issue of parts availability for Sequence V, which evaluates the performance of a lubricant in controlling low-temperature engine deposits, was raised during the discussion. An updated procedure to better simulate current engine sludge issues is required alongside improvements to sludge test evaluation. Fuel consumption is measured for six-speed/load/temperature test conditions in the Sequence VI engine test. This enables a comparative fuel economy index (FEI) of the fuel-saving capabilities of automotive engine oils. Deegan highlighted the need for additional fuel savings and reduced deviation in the Sequence VI fuel economy test.

Concerns were raised around the age of the Sequence VIII test, which has been used since the introduction of ILSAC GF-3 in 2001. The Sequence VIII evaluates crankcase lubricating oils for their copper and lead corrosion control capabilities, along with shear stability under high temperature operating conditions. Deegan called for a resolution on the Sequence VIII to determine whether to remove it from the next category. The engine test will remain for old categories, but something else may be required going forward.  

Analysis of the Sequence IX engine test is also necessary, says Deegan. The Sequence IX evaluates the ability of motor oil to mitigate pre-ignition in the combustion chambers of gasoline, turbocharged, direct injection engines. A review of aged oil LSPI is needed and there was some suggestion an update to the Sequence IX procedure may be involved. There is no change to the Sequence X engine test—which measures a lubricant’s ability to minimise timing chain wear—at this stage although parts availability needs to be evaluated, says Deegan.

He also highlighted several changes to bench tests for the new category, including the addition of the ASTM D129 Sulphated Ash Bench Test with a 0.9% maximum sulphated ash requirement.  

Concerns around seal compatibility mean that seal test changes are also likely for the new specification, with upcoming decisions on whether to keep and/or replace ASTM D7216 – Standard Test Method for Determining Automotive Engine Oil Compatibility with Typical Seal Elastomer. Deegan noted the potential use of the SAE J2979 Compression Stress Relaxation (CSR) test which, he says, OEMs have used to reduce warranties. He also underlined a need to add new seal materials from hydrogenating acrylonitrile butadiene rubber (HNBR), fluro-elastomer (FKM-3), and polyacrylate rubber (ACM-2, AEM-2, AEM-3). In high volumes, ACM is an affordable alternative to HNBR and FKM seals.

Modifications to the Noack volatility test, which determines the evaporative loss of engine oils related to evaporative oil consumption, may be required. Recent research has indicated that standard Noack tests do not correlate well with actual engine oil consumption. Deegan detailed a change to the temperature in the volatility test from 250°C to 150°C for an improved engine to bench correlation. SAE Paper 2022-01-0524¹ has previously demonstrated a good correlation with evaporative oil consumption in actual engine operation with a modified Noack test at 150°C.

Finally, Deegan outlined the need to modify ASTM D6795, which measures the filterability of engine oils. Deegan cited SAE paper 881588² on carbonic acid bubbling which simulates engine oil gelation filter plugging, where water and CO2 were mixed into engine oil to simulate gelation filter plugging.

The Ford representative also emphasised the importance of maintaining backwards compatibility in ILSAC GF-7, the inclusion of low viscosity oils, ethanol fuel use, and the consideration of turbo coking. Protecting for U.S. Environmental Protection Agency and California Air Resources Board requirements was also discussed, as both organisations are currently working on new emissions legislation.  

A request letter for GF-7 to the API Lubricant Standards Group and the Auto Oil Advisory Panel (AOAP) chairs will go out “soon”, says Deegan. The request letter will trigger a host of activities,  including a test review, discussion on funding availability and further evaluation of other potential items. The AOAP is the decision-making body for a new passenger car motor oil (PCMO) category. Tentative implementation timing for GF-7 is the second quarter of 2028, he says.

ILSAC GF-7 will likely include the SAE 0W-8 and SAE 0W-12 viscosity grades. During the meeting, Jeff Harmening, API senior manager, notified the group of API’s intention to submit a request to the AOAP/LSG chairs to add the 0W-8 and 0W-12 viscosity grades to the current ILSAC GF-6B standard. The move would fill an identified gap for the licensing of low viscosity oils in the global marketplace, he says, and could be accomplished quickly and easily.

Harmening indicated that the JASO M366 can be adopted as per API 1509, Annex C, and the GF-6B/API SP tables can be modified to include the new viscosities. The JASO M366 is a test procedure to measure the fuel economy performances of automobile gasoline engine oils using a firing engine test.  ILSAC/API fuel economy limits for JASO M366 would be set identical to the JASO M364 (Automotive Gasoline Engine Oil Standard) fuel economy limits, he says. All other GF-6 /API SP bench/engine test limits would remain unchanged for the new viscosity grades.

API’s Certification Mark “Shield” trademark registration allows for other viscosity grades, as API already incorporated these viscosities into the licensing system when SAE 0W-16 was introduced. API is looking to fast-track licensing, says Harmening. Modifications to typical technology demonstration and mandatory waiting periods can be discussed, he says. If successful, API SP changes would be handled by the API Lubricant Standards Group in parallel.

¹ Koyama, T., Suzuki, T., Yamamori, K., Uematsu, Y. et al., “Research on Ultra-High Viscosity Index Engine Oil: Part 2 – Influence of Engine Oil Evaporation Characteristics on Oil Consumption of Internal Combustion Engines,” SAE Technical Paper 2022-01-0524, 2022.

² Minamitani, H., Hirose, Y., Matsudaira, Y., Kumakura, A. et al., “A Study on Needle Crystals Formation in Engine Oils Containing a Magnesium-Based Detergent,” SAE Technical Paper 881588, 1988, https://doi.org/10.4271/881588.