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 Power Stroke 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 contained more than 1,000 parts per million phosphorus, an effective antiwear ingredient, while some 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.
With the exception of AMSOIL Signature Series 5W-30 Max-Duty Synthetic Diesel Oil, all the new AMSOIL diesel oils provide boosted levels of phosphorus, are recommended for the Ford 6.7L engine and will carry the Ford WSS-M2C171-F1 specification. We have no concerns whatsoever that new Signature Series 5W-30 Diesel Oil will meet the wear protection requirements for the Ford 6.7L engine; however, we are choosing not to include the Ford WSS-M2C171-F1 specification and the 6.7L engine application on this product. Ford has identified a minimum phosphorus level, and Signature Series 5W-30 is below that minimum. Once the 6.7L engine test becomes available (today, it is not yet ready), we will demonstrate the superior wear protection of Signature Series 5W-30 in the Ford 6.7L engine. AMSOIL Dealers and customers can be well-assured that all Ford Power Stroke engines, no matter the model year, are well-protected when using AMSOIL synthetic diesel oils.
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