The Sequence VG (ASTM D6593) measures an engine oil’s ability to control sludge and varnish formation. It is commercially unavailable for the next 120 days due to a lack of reference fuel necessary to run the engine test, API Engine Oil Licensing Manager Kevin Ferrick advised in last weeks letter. Products and formulations that already have API licenses are not affected, he added.

Provisional licensees have until Sept. 14 to pass the test and submit their test data and revised applications to API, but with the test out of action for the next four months, that deadline could prove very snug.

Rules for provisional licensing are spelled out in API 1509. First, as Ferrick explained, a request for provisional licensing of an engine oil must be made to API, using the correct paperwork.

Then applicants must provide proof that their candidate oil is expected to pass Sequence VG. This can be done by submitting passing test results with the same additive in similar base stocks, for example, or results with the same base stocks and different viscosity grade. API 1509 describes other types of acceptable data as well.

Finally, more paperwork: The licensee holding the provisional license must obtain a passing result in the Sequence VG test and provide proof of passing to API by Sept. 14. At that point the licensee can request full licensing of the oil (again by completing the proper paperwork).

If the provisionally licensed oil fails to pass the Sequence VG test by Sept. 14, the licensee must notify API immediately. At that point, API may demand the licensee recall all provisionally licensed oils bearing the API Donut or Starburst trademarks from the market.

Likewise, if the revised paperwork for the provisionally licensed oil is not received by API by Sept. 14, API will cancel the provisional license for that oil and notify the licensee that the oil is no longer eligible to display the API Service Symbol and/or the API Certification Mark. It also will demand that all provisionally licensed oils bearing the API trademarks be recalled from the market by the licensee at the licensee’s own expense.

The impact of this situation could be significant. Once the fuel needed to run the test becomes available, there will be a rush to complete deferred Sequence VG tests prior to the Sept. 14 deadline. Other oils that are not provisionally licensed will be pressing to complete testing, too, and that could create a traffic jam at the engine test laboratories.

Even worse, should a provisionally licensed product not pass the VG in time, removing the oil from store shelves and other distribution points would be problematic for oil marketers. This uncertainty could cause some oil marketers to refrain from provisional licensing, just in case.

Problems with the Sequence VG fuel were spotted by the ASTM VG Surveillance Panel, which monitors the health of the test. It found that a new batch of reference fuel — the fuel that all VG test stands are supposed to use for both calibration runs and for candidate oil tests — was not acceptable.

Infineum’s Andy Ritchie, chairman of the Surveillance Panel, reported on the situation in late February to the ASTM Passenger Car Engine Oil Classification Panel. He noted that the Sequence VG relies on a specially formulated fuel to generate the necessary sludge and varnish formation. Test results showed that VG test runs using the new fuel batch tended to be mild on sludge and varnish, however, and did not discriminate between reference oils.

The VG Surveillance Panel voted to reject the new batch of fuel, and has met weekly by conference call to manage the problem. The fuel blender is also working to resolve the issue, trying to adjust the blend to give more severe sludge results.

But for engine oil qualification and testing, the VG is officially out of service.

Information about API engine oil licensing is at www.api.org/certifications/engineoil/index.cfm.