Valvoline Premium Blue Extreme

[TyCorr]

I ran motorcraft 15w40 in my current 7.3 for about 50k miles. No issues. But I changed it every 3k.

Back to the OP, I've used Mobil1 "turbodiesel" 5w40. I got it for 19.99/gal on sale at oreillyauto. It retails there for 29.99. I don't find the valvoline extreme blue to be any better. I ran that for 20k and switched to the valvoline because everyone sad how great it was. Aside from the cold startup benefits during winter I don't know how great syn is. Sounds like you got it handled by though!

 

[fine69]

I've run Motorcraft 15/40 in my 6.4 since it was new, changed every 3000 miles. Did the same thing in my 6.0 My main reason for wanting to change to the Valvoline was all the people saying how good it is, and I don't drive my truck very much so I thought the cost of Syn wouldn't be a big deal.

 

[lincolnlocker]

i guess if you changed the oil often with motor craft it would be ok... with my truck it wouldnt start worth a sh!t even in summertime after about 1k miles... i know you guys are talking 6.4 but its just crappy oil. had a cousin work at ford and said if you have your oil changed at ford and if they used the bottled oil and not bulk you were ok, but the bulk stuff is actually recycled oil.... and the additive package in motorcraft oil is one of the lowest on the list, below rotella even, i think...