The transition from API CJ-4 heavy-duty diesel engine oils to the new CK-4 and FA-4 lower viscosity oils is proceeding smoothly, according to the API. After almost five years of lab testing and oil development has been completed, approximately 400 CK-4 and 60 FA-4 products have been licensed since December.

Several diesel engine manufacturers are not completely satisfied with these new specifications. But, we must remember that this dissatisfaction could be a commercial matter, rather than a technical one. Engine builders will sometimes try to influence their customers to purchase branded engine oils at a higher cost.

Cummins approves both CK-4 and FA-4 oils which meet their CES 20086 and CES20087 specifications, but it doesn’t endorse all CK-4 and FA-4 oils. Cummins Oilguard program also allows extended oil change intervals with these oils if used oil analysis is conducted using Cummins analytical suppliers. Cummins also allows a 10,000 mile drain interval extension when using Cummins/Valvoline Premium Blue 8600 in their X15 engines.

Detroit has issued a DFS93K222 specification, which CK-4 oils must meet and a DFS9K223 specification for API FA-4 oils to meet. Detroit is using an FA-4 oil for factory fill on its DD13, DD15, and DD16 engines. The engine OEM is also introducing an Efficient Long Haul specification for extended oil change intervals.

Ford is recommending the use of its new Motorcraft diesel engine oil for Super Duty trucks. They are warning commercial customers to avoid using most new CK-4/FA-4 oils due to concerns about high-mileage wear rates.

Ford is telling fleets not to use CK-4/SN oils unless they have proven to meet the Ford WSS-M2C171-F1 specifications. Apparently this specification will approve only SAE XW-40 grade oils, not XW-30 grade oils. This suggests to me that Ford’s 6.7L diesel may be having high-temperature wear problems. Fiat Chrysler encountered a similar problem with their Eco Diesel engine last year, only theirs was biased towards excessive low temperature wear. They eventually banned the use of 5W-30 oils and required the use of 10W-X or 5W-40 and thicker oils in their service bulletin.

International is promoting a 70,000-mile oil drain interval with their A26 MAN-based engine family. This is no surprise, given their recent alliance with Volkswagen—European companies have recommended longer oil change intervals for years.

Kenworth recently announced a 60,000 mile oil change interval for its fleet vehicles. This is accomplished by utilizing a larger oil sump combined with a centrifugal oil filter. The added volume is sufficient to extend drain intervals.

Mack has also introduced the concept of extended oil change intervals only when using its proprietary Mack EOS-4.5 engine oil. Mack claims the new EOS-4.5 oil is a proprietary formulation that is better than CK-4 spec oils. This oil is backwards compatible with all engines using API CJ-4 and CK-4 oils.

Volvo has been silent thus far, but I expect they will use an approach similar to Mack.

Cummins started this proprietary engine oil trend in the U.S. But in Europe, two factors support this reasoning. First, there are few aftermarket maintenance shops, and so truckers are forced to use dealerships to do maintenance. Second, there are few large fleets in Europe, so diesel OEMs can use the warranty lever (even though it’s not legal in the U.S.) to encourage the use of their proprietary oils.

The situation is different in this country. As one large fleet executive once told me, “I do what I please.” Their purchasing power overrules all warranty considerations. However, if you are a smaller operation, it might be smarter just to “go with the flow” until the warranty period is over. Size does matter!