Preference on Motor Oils

[Offrd19]

I have read customer reviews that have stated 2.5mpg gains from more expensive motor oils. Just wondering if the Amsoil's and the Royal Purples are worth the extra bucks.

[drz400smoto]

Im running amsoil... haven't noticed any mpg gains. The truck runs good, but Im debating if im going to keep using it because its soo expensive and these trucks take so much oil.
I might switch to a cheaper synthetic oil.

[fordmasterdieseltech]

Run motorcraft 10w30 cj-4 diesel motor oil year round. cold starts are greatly enhanced. I run it in my truck year round.

[topdwg]

I run anything I can find on sale...haha. I here recently put in some Delo 400 that I got on sale for 9.99 a gallon at Advance. I typically use either Valvoline or Rotella though. Only reason I went this route was because I heard some good stuff about it, and it was on sale.

[ClarkSJ]

I was skeptical, but changing to Rotella T6 5w-40 full synthetic from Motorcraft 15w-50 dino oil really quieted down my engine at both startup and when it warmed up. Very noticeable difference. I haven't looked for an increase in MPG, but based on this I'm gonna stay with a full synthetic for this truck.

[JohnnyFive]

changing to Rotella T6 5w-40 full synthetic from Motorcraft 15w-50 dino oil really quieted down my engine at both startup and when it warmed up. Very noticeable difference.

I have not noticed an increase in MPG but I am switching to Rotella synthetic for the very reason as ClarkSJ. I've heard this from several F250 owners and will be giving it a shot in less than 1,000 miles.

[swamp_ratt]

i will ONLY run Shell 15w40 dyno or Amsoil 15w40 synthetic? dont trust nothing else in a diesel engine

[swamp_ratt]

also run lucas oil stabilizer with my shell and lucas synthetic oil stabilizer with amsoil. 20%

[Rohan]

I change my oil about every 6 weeks so use the cheapest I can find for now. I'd be willing to test out that Rotella synthetic stuff at some point though.

I used to use Rotella T 15w40 on sale at Advance Auto for 9.99. then I found this stuff at TSC (Tractor Supply Company) for 7 bucks a gallon and have been running it for 3 oil changes now. I haven't noticed any difference b/t rotella and the travelers stuff from TSC

[ianstew]

The 5w-40 syn is good for cold weather starts, etc, and off the shelf synthetics are pretty good stuff, Amsoil, Royal Purple, etc is a waste of money IMHO, I am very skeptical of any manufacturer or user claiming MPG gains from any oil or additive.......I fully beleive an engine will last just as long using MC or Rotella as it will using Amsoil or others at much higher prices. At my old job we had many many high mileage 6.0's that never had problems, and always used bulk 10-30 diesel oil...........