Oil choice for the 6.4

[Texas_Bear]

I sell AMSOIL and ran it in my Harleys and my old DMAX, so I always thought it was no question! However, after seeing some posts on this site about AMSOIL not running so good in the 6.4 PSD, I decided to conduct a little further research. I ended up spending $88 by going with the Mobil 1 Synthetic 15W40 for "Turbo Diesel Trucks". Then I spent some valuable time talking to one of the Ford Diesel Techs at one of the local dealerships. He suggested to always run the Motorcraft Oil Filters, but synthetics just aren't worth it in the new 6.4 because the oil needs to be changed more frequently. They actually had some engine failures because people were not changing thier oil until around 12 - 20K! He recommended I change my oil between 5 - 8K to be safe. You see the 6.4 actually produces oil by allowing fuel to flow into the oil, thus producing more oil than the original 15 quarts you installed! Therefore, common sense will tell you, just run a good conventional proven oil like Shell Rotella T or something comparable; save yourself $44 since you have to change it more frequently anyway! Just my 2 cents worth of advice!

[DavidPhillips]

Unless you go where it's extreme cold and must have synthetics for cold starts then use regular oil.

You need to change it every 5000 miles.

Saying how great synthetic oil is don't cut it. You have to do a lot of tests on a lot of engines under a lot of conditions and take them all apart. This has not been done to my knowledge on the 6.4 or any other engine. They all use some bizarre form of testing that has absolutely nothing to do with the oil in your engine.

Your regular oil is good for just as long as any synthetic oil is in your motor. The oil will be contaminated if you leave it in too long and it does not matter what type it is.

Unless your going to do oil samples to determine change intervals you need to change it every 5000 miles.

If however you drive only highway and never idle or have short drives or drive in extreme cold you could probably go closer to 10000 miles on either type of oil.



There have been a lot of people that have had problems with synthetics in these engines. Weather it's true or not is not worth the risk for me. I use Motorcraft oil and "my truck runs great".

[Hit Man X]

Red Line, front to rear here.

[nsrchofpwr]

i have always run chevron delo 400. i just changed to synthetic at last oil change. i used to change oil around 5,000 miles. now i don't know if i can go past 5,000 or not. probably won,t. to kill a great engine over a 100 dollars to me is not smart!