Sequence IVB Test Suffers Setback

The last engine test for ILSAC GF-6 failed this month to gain acceptance into the passenger car engine oil classification, a critique that the proposed method does not adequately gauge the ability of oils to prevent engine wear.

The outcome means the Sequence IVB test still needs more work before the automobile and lubricant industries can begin to finalize a timeline for the much-delayed GF-6.

The Auto/Oil Advisory Panel, a committee that jointly represents the International Lubricant Standardization and Approval Committee (automakers) and the American Petroleum Institute, reviewed the ballot for Sequence IVB on April 5. The proposal to accept the test into GF-6 - conducted remotely over the latter days of March and first few days of April - failed by a tally of 5 affirmative votes, 7 against and 11 abstentions on the oil side of the vote. The auto side voted unanimously to accept the test into GF-6, by a vote of 11 in favor, and none against, and no abstains.

All AOAP panel members voted, and those representing lubricant and lubricant additive companies expressed many reservations about the tests readiness. Many of their comments were similar no matter how they voted. Key concerns included the tests ability to discriminate between reference oils known to provide adequate wear protection and those that do not; its repeatability and reproducibility, or ability to yield consistent results for oils tested multiple times or in different labs; and the fact that it does not measure wear in the same way as the Sequence IVA, which it is supposed to replace. Some panel members worried this would prevent GF-6 from ensuring adequate low-temperature wear protection especially in older engines recommended to run on earlier generation oils.

The Sequence IVB was designed to test valve train wear by measuring average volume loss of intake lifters. Since questions arose about its ability to do this, panel members have considered also measuring the level of iron in used oil samples post-test as a gauge of overall wear throughout the engine. Ron Romano of Ford, who provided the lone comment on the auto side, supported adding an end-of-test iron limit to the Sequence IVB and working through any remaining issues without stopping the test from being accepted into the category and used now.

Automakers are eager for the test to be accepted so they can proceed to set a timeline for first licensing of GF-6. The classification is currently on track to come to market during the first half of 2020, four years after the original target, but that date could slip further if the Sequence IVB is not resolved soon.

Panel members suggested a variety of ways forward. Valvolines representative, who voted affirmative, suggested renaming the test the Sequence XI and retaining the Sequence IVA for a time since the new test is not a direct replacement. Another proposal suggested that the Sequence IVB be used for some period not as a classification requirement but only to generate a database of results that could be used to refine it and determine a limit later in the process. Again, the Sequence IVA could be used in the meantime, though the parameter limiting phosphorus content today would need to be changed from a simple cap on the chemical to a cap on phosphorus coming from zinc dialkyldithiophosphate.

Still another proposal called for retaining the Sequence IVA only for GF-6A, which will be used for both current and legacy engines, and setting a higher limit on the Sequence IVB to prevent false failures of the average intake volume loss or used oil iron content.

The Surveillance Panel provided updates on its work to AOAP, including a report on the status of the Sequence IVA. The existing test currently has three calibrated engine test stands at the two independent labs and the ability to run over 400 tests. It was projected that this would be enough capacity to manage current categories, including the upcoming API SN Plus, for about five years, but there is not enough capacity if the Sequence IVA is also used for ILSAC GF-6. The panel also re-affirmed that Nissan no longer has the ability to manufacture parts for the KA24E engine used in the Sequence IVA test, which suggests that continued use of the IVA may not be a practical solution.

It should be noted that there is still broad support for the Sequence IVB to be included in GF-6 when issues are resolved and the test full meets the GF-6 needs statement for wear protection of components. Industry resources are working hard to develop a solution for the Sequence IVB that will allow GF-6 to move forward, but until then a final schedule for ILSAC GF-6 will have to wait.