The Lubricants Committee voted over the last three months to move both categories off the list of licensable products. The decisions came when engine tests used to define the categories became unavailable. This action follows closely behind the decision to obsolete the API CG-4 category, which was done August 31, 2009.

The API CF category was introduced in 1994, and defined oils intended for use in off-road, direct-injected and other diesel engines using high-sulfur fuels. The CF-2 category, also launched that year, was intended for severe duty, two-stroke-cycle diesels.

Their death was foretold when diesel engine builder Caterpillar decided to stop supporting the Cat 1M-PC single-cylinder engine test, which is a key requirement for both. At last month’s ASTM Committee D-2 meeting in Anaheim, Calif., Caterpillar confirmed that parts for the 1M-PC are no longer being made. The 1M-PC test is based on an outdated piston/ring design and is run on hard-to-obtain higher (0.4 percent) sulfur fuel. Globally, the sulfur content of most diesel fuels is dropping towards the 0.05 percent range, although it may continue to be much higher in some geographic areas.

Also at the ASTM meeting, independent engine test laboratories said there is an estimated six months’ worth of Cat 1M-PC parts available, so there may be a few final tests run for API CF products. This may help engine oil formulations that want to claim they meet the “former API CF performance,” even after licensing ends.

Likewise, the Detroit Diesel 6V-92TA test, needed to license products for CF-2, is no longer available. The 6V-92TA uses a six-cylinder, two-stroke-cycle diesel to ensure engine oil performance. Such engines, primarily made by Detroit Diesel, were used in off-road equipment as well as in many military vehicles. While there are still a number of two-cycle diesels in the field, most now run on oils of more recent vintage, such as API CH-4 or CI-4.

Kevin Ferrick, manager of engine oil licensing at API in Washington, D.C., told Lube Report that some 10,000 total engine oil products are covered in the program. Of these, a surprising 200 are licensed to CF-quality in the United States, plus another 450 outside the country. Worldwide, there are 70 products licensed to CF-2 alone, and about 700 licensed to CF/CF-2 together.

Few CF and CF-2 products appear to be sold in the U.S. diesel engine oil market. However, these categories find wide use as cost effective, straight-grade engine oils in markets such as Latin America, where they hold a substantial share.

At the ICIS Pan American Base Oils & Lubricants Conference in December, for example, Roberto Vargas of Lubrizol reported that 42 percent of the heavy-duty diesel oils sold in Mexico are API CF, and another 25 percent are CF/CF-2. In Brazil, Flavio Gusmao of Petrobras told the conference, the market share for API CF is a strong 33 percent. Replacement oils for such markets will probably be licensed to the API CH-4 or CI-4 categories.