The Mack T-12 engine wear test has returned to service after a 6-month hiatus, the ASTM Mack/Volvo Surveillance Panel announced on September 10. All API CH-4, CI-4, CI-4 Plus, CJ-4, CK-4 and FA-4 heavy-duty engine oils with a provisional license must pass the Mack T-12 test by March 10.

Once a formulation has passed the Mack T-12, the licensee should enter a new formulation in API’s online application system and apply that formulation to each affected product before submitting to API for review. Once the new formulation is approved, API will withdraw the provisionally licensed formulation. 

If a provisionally licensed oil fails to pass the test, the licensee must notify API immediately and take whatever corrective action the institute deems necessary within a certain timeframe.

If API does not receive a new oil formulation by the end of the six-month period (March 10), it will cancel the provisional license for that formulation and any associated products. With no active license, marketers may no longer use the API “donut” service category logo on the product.

The Mack T-12 test was pulled in March when a new batch of parts led to higher-than-normal oil consumption. API found that the batch of piston crowns contained a group of parts that were responsible for the higher oil consumption, David Brass, chair of the Mack/Volvo Surveillance Panel, wrote in a letter dated September 10. The surveillance panel agreed to
industry correction factors for the batch of parts, and test labs were to have obtained calibrated status by September 13.

Questions may be directed to EOLCS.