The launch of the new API diesel oil specifications in December will prompt a significant change in the AMSOIL synthetic diesel oil lineup. Premium Synthetic Diesel Oil and OE Synthetic Diesel Oil will be discontinued, replaced with new API CK-4 synthetic diesel oils in February.

Like Signature Series Synthetic Motor Oil for gasoline engines, Signature Series Max-Duty Synthetic Diesel Oil will represent the top tier of AMSOIL protection and performance for diesel engines. Signature Series will be available in 5W-40 and 15W-40 viscosities, as well as new 0W-40 and 5W-30 viscosities.

AMSOIL Heavy-Duty Synthetic Diesel Oil will provide outstanding protection and performance for customers seeking an upgrade over conventional and synthetic-blend diesel oils, while being price-competitive with other synthetic brands in the marketplace. AMSOIL Heavy-Duty Synthetic Diesel Oil will be available in 15W-40 and 10W-30 viscosities, as well as a new 5W-40 viscosity.

AMSOIL Synthetic Diesel Oils covering the new API CK-4 specification will be backward compatible with the current CJ-4 and older specifications.

There will also be a new API diesel specification, FA-4, which will NOT be backward compatible. Only the CK-4 diesel oils are backward compatible.

The new FA-4 classification is being required for new engines (2017+) that require a lower viscosity.

Outstanding Protection for Ford* Powerstroke* Engines

Ford Motor Company recently released its position on the upcoming new API CK-4 and FA-4 diesel oil specifications, claiming it will only recommend diesel oils that meet the Ford WSS-M2C171-F1 specification or oils formulated specifically for the previous API CJ-4 specification.

Questions have arisen regarding why Ford would condemn use of CK-4 and FA-4 products in its Powerstroke engines. According to Ford Service Lubricant Technical Expert Ron Romano, “6.7L engines tested on CK-4 and FA-4 formulations had experienced valve train wear not encountered with CJ-4 formulations. The CJ-4 formulations in question contained more than 1,000 parts per million phosphorus, an effective antiwear ingredient, while the CK-4 and FA-4 formulations were below that threshold. As a result, Ford declared that it has wear concerns about the use of CK-4 and FA-4 formulations with less than 1,000 ppm phosphorus in new and older Ford engines.”

All current AMSOIL synthetic diesel oils contain a boosted level of wear protection above the requirements set by the Ford specification. The new AMSOIL Signature Series Max-Duty Synthetic Diesel Oil and Heavy-Duty Synthetic Diesel Oil formulations launching in February will also contain boosted levels of wear protection, and they will carry the Ford WSS-M2C171-F1 specification. AMSOIL Dealers and customers can be well-assured that all Ford Powerstroke engines, no matter the model year, are well-protected when using AMSOIL synthetic diesel oils.

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