The Sequence VG test uses a 4.6 liter V-8 engine supplied by Ford, and is the main North American test for evaluating engine oil’s ability to control sludge, which historically was associated with poor fuel quality and certain fuel additives. The test relies on a specially formulated fuel to generate high levels of sludge and varnish that are measured during reference test runs. When a batch of suitable reference fuel could not be secured, the VG test became unavailable and licensing of many API engine oils was disrupted.

In recent years fuels have become much “cleaner” than they used to be so sludge concerns are less common, explained Andy Ritchie, chairman of the ASTM Sequence VG Surveillance Panel which monitors the test’s health. A wave of sludging problems was seen in the last decade, but was blamed not on fuel quality but on consumers using longer oil drain intervals than recommended by their vehicle manufacturers.

However, sludge issues may reappear in countries where poorer fuels can be found, observed Ritchie, who is with Infineum, and the auto industry remains adamant that it needs an engine test to screen lubricants for sludge protection as part of the requirements for certifying any new engine oil.

In late February, after the VG Surveillance Panel found that a new batch of test fuel was unable to generate acceptable levels of sludge and varnish, or to show discrimination between the amount of sludge generated by “poor” and borderline VG reference oils, the ASTM Passenger Car Engine Oil Classification Panel advised API to take steps to allow provisional licensing of oils until the Sequence VG was reinstated.

On April 6, in accordance with rules spelled out in API 1509 (the Engine Oil Licensing and Certification System), API issued a provisional licensing letter reflecting the fact that the Sequence VG test was unavailable. The Sequence VG engine test was declared commercially unavailable for 120 days due to the lack of a test fuel necessary to run the engine test. Expecting that the fuel question would be answered within a short period of time, all provisional licenses would need to be completed by Sept. 14.

Meanwhile, the fuel supplier, Haltermann Solutions, worked on the problem and by early summer produced a new batch of fuel which was successful in generating acceptable levels of sludge and varnish. On July 29, the VG Surveillance Panel approved this fuel.

That gave the green light to Thom Smith of Valvoline, who chairs the ASTM Passenger Car Engine Oil Classification Panel, to formally notify API that the new batch of fuel was in place. This fuel is now available to all engine test labs, making the Sequence VG once again commercially available.

While the process to reestablish the Sequence VG has been both costly and time consuming for the industry, Ron Romano of Ford Motor Co., the test sponsor, believes that there have been some benefits from the recent exercise. He commented that the ASTM VG Surveillance Panel and the newly restored Operations and Hardware Panel, which is chaired by George Szappanos from Lubrizol, both have made great strides in reinvigorating the ASTM VG Panel activities and processes.

Romano added that these groups now are better prepared to address the challenges which are sure to come while introducing the new Sequence VH test, the upgrade of the VG test which is beginning its development. If all stays on track, the VH test is projected to begin the process of becoming an ASTM standard starting some time in 2013.

Andy Ritchie echoed Romano’s sentiment, saying that the development of an acceptable new VG fuel batch was an excellent example of the value that ASTM provides, bringing knowledgeable individuals together to work on and solve a problem of this type.

Meanwhile, today marks the deadline for provisionally licensed oils to have completed their testing and filed complete applications with API. If a provisionally licensed oil had failed to pass the Sequence VG test by today, the licensee would have to notify API immediately, and API could demand the licensee recall from the market all provisionally licensed oils bearing its Donut or Starburst trademarks.

Given the extra paperwork, expense and risk involved, industry insiders had predicted back in April that API was unlikely to field many requests for provisional licensing. As it turns out, not a single provisional license was issued while the VG was on hiatus, according to Kevin Ferrick, engine oil manager at API in Washington, D.C.

However, now that testing has begun again, industry sources believe there could be a last-minute rush to complete testing programs that were delayed by the VGs absence – especially since all old ILSAC GF-4 engine oil licenses are due to expire on Oct. 1, when that category dies.