It added to a series of such disruptions that have hit the market’s engine oil licensing system the past few years as problems with test availability become more frequent.

The Mack T-12 test is used to measure an oil’s ability to prevent wear in turbocharged intercooled diesel engines that are equipped with exhaust gas recirculation and that operate on low-sulfur fuel. The test is required for the two newest industry heavy-duty oil specifications in North America – API CK-4 and API FA-4 – as well as four earlier specs that are still active: API CJ-4, API CI-4 Plus, API CI-4 and API CH-4.

The trade association said it invoked provisional licensing after being informed by ASTM D02.B02 Volvo/Mack Surveillance Panel that independent labs conducting third-party tests to measure the performance of candidate oils could no longer run the Mack T-12. A hardware problem is preventing labs from referencing engine test stands that would be used to test candidate oils, according to an industry source.

In a March 17 news release, API advised that the provisional licensing would last until Sept. 17. During provisional period, marketers seeking new licenses for the mentioned specifications can receive a pass on the Mack T-12 requirement by advising that the test is not available. Candidate oils still must pass all other requirements.

API will list provisionally licensed oils in its directory of licensed oils without denoting that they did not pass the wear test. The organization stated marketers are still responsible for the performance of their products.

Once provisional licensing is lifted, oils that were provisionally approved will have six months to pass the Mack T-12. If an oil fails that test, marketers are required to immediately notify API and to take corrective actions such as product recalls. Marketers of oils that fail to take the test within six months will have their licenses revoked.

API allowed the possibility of the provisional period being extended beyond Sept. 17.