Fuel-economy Test Snafu Still Unsolved


Questions regarding the reliability of the Sequence VIB (“Six B”) engine test, which is supposed to demonstrate the fuel economy properties of passenger car engine oils and is required to license the new GF-4 oils, have been sent back down the pipeline for a closer look by ASTM’s Sequence VIB Surveillance Panel — the group which first raised a red flag regarding the test’s performance three months ago.

On Sept. 17, Charlie Leverett of PerkinElmer Automotive Research, who chairs the panel, advised that neither of two GF-4 licensed engine oils that marketers had offered as Six B reference oils “could perform at the GF-4 pass limits when run in calibrated industry test stands in multiple laboratories.” Reference oils are used to calibrate engine test stands, and help ensure that every laboratory is running the test correctly. Each of the two proffered 5W-20 oils was tested five times and neither made a passing grade.

Perplexity greeted this announcement because both the oils had GF-4 credentials and had earlier passed the Six B. Concern also arose because each test run cost $25,000, for a total industry outlay of $250,000 on the miscarried effort. (See Lube Report, Oct. 20.) Leverett’s panel was unable to nail down any reason for these test failures and was reluctant to engage in any further testing for purposes of finding another reference oil because of the costs involved.

Experts reassured that there would be no impact on the testing system from these failures, and Six B testing can continue. “All other lubricant engine tests, both light- and heavy-duty, have at least one dedicated reference oil in our inventory,” reported John Zalar, director of ASTM’s Test Monitoring Center.

“The failure of these oils as a VIB reference oil,” he emphasized, “does not mean that Sequence VIB test stands can’t be calibrated. Two other reference oils are available for this purpose.”

PerkinElmer’s Tom Franklin, chairman of ASTM Subcommittee B on Petroleum Products and Lubricants, which met in early December, said Subcommittee B’s Passenger Car Engine Oil Classification Panel had the question “under consideration but a simple resolution seems unlikely.”

Prior to the meeting, the Classification Panel’s chairman, Chevron Oronite’s Frank Fernandez, had written to suggest a handful of options for resolving the concerns and others were contributed by his panels members.

Little support was presented for four of these options: to further investigate whether the test has shifted in severity; look for another SAE 5W-20 reference oil; choose a different SAE grade oil as a candidate Six B reference oil; or request that the Six B GF-4 test limits be revisited. Two options — introduce a statistical test correction factor, and declare the test out-of-control — were lightly supported, with only one company favoring each.

Three options gained considerable support and were sent Dec. 8 to the Surveillance Panel for consideration:

1. Do no further work in development of a GF-4 capable reference oil for the Six B. Future referencing of the test should be conducted with existing reference oils.

2. The Surveillance Panel should continue in earnest to improve test precision. Six B test precision is generally recognized as inadequate, and may be a complicating factor in understanding the data recently generated on two proposed GF-4 reference oils.

3. While not the purview of the Surveillance Panel, several Classification Panel members observed that the experience gained in the effort to develop a GF-4 capable reference oil should be instructive, and urged the lessons learned not be ignored when limits for GF-5 — the next engine oil upgrade — are developed.

On Monday, Charlie Leverett told Lube Report that Fernandez’s letter will be discussed at the next Surveillance Panel meeting, next year. His PerkinElmer colleague John Glaser pointed out that a comment in Fernandez’s letter neatly summed up the core mission of all surveillance panels, “working together to improve test reliability.”

So, three months after having raised the specter of failing Sequence VIB reference oil tests, and with a thorough and helpful review of the issue by several industry technical venues, the issue reverts back to where it originated — ASTM’s Sequence VIB Surveillance Panel — for ongoing consideration.

Concern over the Six B’s reliability reached beyond ASTM’s committees and panels. Hearing of the test failures, the quick-lube industry’s Automotive Oil Change Association immediately wrote to both ASTM and the American Petroleum Institute, on Oct. 20, stating that “the widespread level of failure in this case is of extreme concern to us.” AOCA’s Steve Christie insisted the problem “needs to be corrected immediately before any further unnecessary risk and expense are incurred by the fast lube industry and its customers.” (Lube Report, Nov. 24)

ASTM Subcommittee B’s Tom Franklin responded promptly to AOCA. “My own observations,” he wrote, “based upon the statistical variations that exist for the Sequence VIB test and the current industry ratio of passes to fails, are that a) products qualified using the Sequence VIB meet the letter of the GF-4 specifications with respect to fuel economy, and b) these oils will provide your customers with the best fuel economy available with current lubricant technology.”

API’s Lubricants Committee, on the other hand, considered AOCA’s letter at its Nov. 8 meeting and agreed that a response was in order. On Monday, however — two months after receipt of AOCA’s letter — an API spokesperson stated that it “expects to deliver a response after the first of the year and has nothing early or draft to share with the news media at this time.”

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