The choice to extend is up to him.
I try, as best possible, to clarify my statements with qualifications. I would not extend the OCIs when factory warranty is in play. On some engines, it's a very low risk and perhaps worth taking.
But the 6.7L engine family is fairly new, the total history is still developing, and it's a VERY expensive engine to have to work on or replace. Thoughtful sense dictates that OEM OCIs per the IOLM would be prudent in this case.
He wanted to know if there is anything wrong with running 15w-40 Delo; I would say that there is not. He stated that he's not going to extend the OCIs; that would be sensible in this case. Ford requires a CJ-4 rated lube; they only "recommend" 10w-30 or 5w-40.
Taken directly from the 2012 Diesel supplement, 3rd printing:
"5W-40 or 15W-40 oil is recommended for fuels with greater than 5% biodiesel (B5).
and this:
"For normal or severe service, use Motorcraft oil or an equivalent oil conforming to
Ford specifications as listed in the Maintenance product specifications and capacities section in this chapter or API service categories CJ-4 or CJ-4/SM. (underlined emphasis by dnewton3)
and this:
The following conditions define severe operation for which engine operation with SAE 5W-40 API CJ-4 is recommended.
There is a difference between what is recommended, and what is required. Any CJ-4 approved lube is all that is required. The grades matter only in that they are preferred, not a necessity. As you can see, Ford allows for many grades and recommends upon many differing inputs, but they only "require" CJ-4 rated lubes.
In this case, it is a game of semantics with words ...
For several years, Ford put something to the effect of "BP fuels recommended" on the gas filler caps of the gasoline vehicles they made (I'm paraphrasing here; cannot recall the exact wording). Does that mean that I have to use BP fuels? No - it does not. Just because Ford recommends something, does not mean it's required. What is "required" will be fairly spelled out; it's a condition of the M/M act where they are compelled to tender the conditions upon which warranty is predicated. But that law does NOT require them to be exclusive; they can include "recommendations" along with the "requirements". There is already case law from years ago that allows for variation from "recommendation". Only "requirements" are to be adhered to in warranty compliance. That does not stop OEMs from offering their preferences, but you are not mandated to follow them. Your only obligation to comply with warranty is to follow the "requirments" or other mandates; they must be cleary stated, but can be imbedded into other (less than obvious) intent.
Given that his vehicle is under warranty, and in his area (Portland) I see the pragmatic approach to be OEMs by IOLM and a lube that is CJ-4 licensed; nothing more is "required". The Delo 15w-40 will be fine and he will be in warranty compliance with that licensed lube that is in a grade allowed for by the Ford criteria.
From there on, the choice is his to make. He now has the information available to make up his mind. He can chose by facts or emotion; either path might make him happy.
