The retirement of the API categories CF and CF-2 (Never Say Never, July 2010, page 6), leaves no category within the Engine Oil Licensing & Certification System (EOLCS) in which a monograde diesel engine oil can be API licensed. That may not be a big deal with current engines and OEM recommendations, but on the heavy-duty off-highway side there are a significant number of older vintage engines still operating. It is not unusual to find these engines in service and operational after 30 or 40 years.

Heavy-duty categories began their progression toward multigrade categories with CE. Today it is technically impossible to pass API CJ-4 test requirements with SAE 30, 40 or 50 grade oils. This leaves owners of these diesel engines without an API category to specify the oils they need. Most of these engines are found in marine, construction and generator applications.

Alco, Fairbanks-Morse, Wartsila and Paxman are a few of these engine brands that specify monograde oils. While some of the parent companies may no longer exist, parts and service do. The designs of these engines are quite different than current engines: indirect injection, aluminum pistons with low fire rings, no turbocharging. These engines were designed to run on API CD monograde oils.

If supporting tests are discontinued certainly the category can no longer be viable, however to ignore customers requiring monograde oils leaves the EOLCS incomplete. Possibly API could consider a read-across process that such oils could be licensed if based off a licensed CH-4 formulation, for example, and designated CH.

Dan Larkin

D&L Lubricant Solutions Inc.

Sterling Heights, Mich.