The spec is called “WSS-M2C171-F1,” which – we think you’ll agree – rolls right off the tongue and no one will have any trouble remembering, ever. Ford is presenting it as a friendlier alternative to the new CK-4 specification, as some oils meeting CK-4 standards have been found to lead to accelerated wear in the new 6.7L Power Stroke due to their low phosphorous content. Ford recommends using CJ-4 oils in a pinch, but that oil is currently being phased out.
Ford, through its Motorcraft parts brand, will shortly begin selling its own WSS-M2C171-F1 oils for Power Stroke diesels, but in the meantime, there’s another option: some CK-4 oils have been tested and approved to meet WSS-M2C171-F1 standards. They are available in SAE 10W-40, 15W-40, 5W-40, and 0W-40 grades; SAE 10W-30 oils made to CK-4 spec cannot be compliant with WSS-M2C171-F1.
For more, watch the video above.