best synthetic oil

[fx4superduty33]

I have an 08 superduty with 49,000 miles on her and i just put on a h&s black maxx tuner and 5" flo-pro dpf delete exhaust with afe intake. I just switched to mobil one 5w 40 sytheteic oil and im not sure im liking the mobilone oil. What are some other options on synthetic oil thats out there and can i switch back to the ford 15w 40 now that i have gone synthetic for only one time?

[j21black]

Is the Mobil One CJ-4 rated? All of it I looked at was not.

I am changing my oil every 5k and saw no reason to run the Syn Oil. I am sticking with Rotella 15w40.

[PolarBear]

You can switch back to the Ford 15w-40 anytime you want, or any other oil for that matter. It won't hurt a thing. There's probably a dozen threads about which synthetic to run in the 6.4 and there's really no solid answer to what's best. Mostly personal preference and past experiences. The main thing is to not go for the longer drain intervals which seems to be leading to alot of premature engine failures down the road. Some of the main brands guys are using are the Mobil 1, Amsoil, Valvoline, Rotella to name a few. I've only ever run Motorcraft 15w-40 but will probably be choosing a synthetic when I get a 6.4. What's making you dislike the Mobil 1?

[dieselkane]

I'm a big fan of the rotella 5w40 fully synthetic

[11SuperDutyKR]

I'm a huge fan of Valvoline now after switching over from Rotella. My truck has 111k miles on it.

[Clayton1985]

Originally Posted by dieselkane

I'm a big fan of the rotella 5w40 fully synthetic

Also what Im currently using.

[scottbolt]

i have used all of it from rotella to amsoil to sheffield to mobil one i have found amsoil being the best the only problemk is the multi level marketing they do it drives the price of the stuff up! i have a amsoil oil bypass unit on my 6.4 and a sinister diesel coolant bypass i have a leak in my radiator which when i replace it i am going with amsoil antifreeze but the guy is right its pretty much preference! but look up the amsoil web site they do have a lot of good stuff i tried some of there diesel concentrate and it gave me another mile per gallon on fuel milage!

[dieselkane]

Originally Posted by 11SuperDutyKR

I'm a huge fan of Valvoline now after switching over from Rotella. My truck has 111k miles on it.

Just curious, what improvements have you noticed with the valvoline over the Rotella? Maybe I'll try it next. I've had great UOA's with the Rotella so far.

[11SuperDutyKR]

^I've been running the valvoline for about a week now, and already the engine noise has decreased and I have almost zero injector rattle(talking cold starts here, never had any rattle under normal operating temps) even on extremely cold starts. Usually a little injector rattle is normal, and I was getting some on Rotella. I have no actual facts to prove that valvoline has done anything better than rotella, but it's hard to believe it hasn't going by how smooth it sounds now versus before.

[tricktom1]

Is anyone that's switching oils having them analyzed to determine that one is better than the other?