2002 7.3L Powerstroke

[DocB]

Regarding a 2002 F-350 7.3L Powerstroke with a Bypass Oil Filter and Amsoil Diesel Motor Oil.
Is their 15w40 Heavy-Duty Diesel and Marine Oil still the best oil to run for long OCIs?
Have been using the Diesel and Marine Oil with great success but see that they have some new 15w40 out and don't even list my oil anymore for my truck as a recommended oil.
Asking here because of the forums historically valued unbiased advise. TIA.

 

[maineiac]

I owned the 7.3 Powerstrokes in two F250s and one F350. Great engines overall, just keep a spare CPS in the glovebox and don't forget the SCA! I did not run extended OCIs in these engines as the HEUI system is legendary for shearing oil. If you do go to extended OCIs, make sure that you do used oil analysis to insure that the oil is remaining in grade.

 

[DocB]

Have been doing UOA and am due for an oil change, hence the question. Guess I will call Amsoil Monday, but I have a feeling I already know what they are going to say.
Not knocking them, I love their products, but would like to do what is best for me and my truck.

 

[jeepman3071]

I see they still list the Heavy Duty Diesel and Marine 15w40 oil under their Diesel oil products, just not as a recommended oil for your truck. Maybe they feel the two products listed for your truck have superior specs and the Diesel/Marine is a lesser oil for the HEUI system? I know if you speak to a rep you will likely get recommended what is listed for your truck, as you suggested, but maybe the rep could explain why they have changed the recommendation. My guess would be the recommended oils are better for the application.

 

[LubricatusObsess]

Amsoil says on their website their diesel oil meets Ford's antiwear spec for HEUI high pressure oil pumps. WSS-M2c171-F1

Ford does not list them on the approved vendor list (attached below). Whether Amsoil meets the spec or not, we are left to speculate. Amsoil says "trust us". We say "show us your data". They say "uh-uh".

https://parts.ford.com/content/dam/..._Motor_Oils_Meeting_Ford_WSSM2c171F1.pdf