Rotella T causing low fuel mileage?

[HeavyHauler]

I've heard some talk about Rotella T causing low fuel mileage on the Cummins. Can anyone back this up? Anybody tried Rotella T and compared the mileage to another brand of oil?



Also, would it hurt anything if I tried different oils over the next few oil changes? My truck has 60,000 on it and has had Rotella T in it since it's first oil change. I'd like to try out Castrol RX and Delo 400. I had always heard that it's best to stick with one type of oil but I thought that might be just dumb country boy talk.



Thanks for the help.

 

[BreaksEverything]

Originally posted by HeavyHauler

I've heard some talk about Rotella T causing low fuel mileage on the Cummins. Can anyone back this up? Anybody tried Rotella T and compared the mileage to another brand of oil?



Also, would it hurt anything if I tried different oils over the next few oil changes? My truck has 60,000 on it and has had Rotella T in it since it's first oil change. I'd like to try out Castrol RX and Delo 400. I had always heard that it's best to stick with one type of oil but I thought that might be just dumb country boy talk.



Thanks for the help.

just dumb country boy talk.



to try out Castrol RX and Delo 400.

it won't hurt , they're both just fine too run

 

[rrausch]

One of the least understood results of changing to different motor oils is that different brands of oil deposit sediment in different places in the engine. The last I read, no one really understood why this should be, but it apparently is a fact. It probably won't hurt to change around a little, to find an oil you feel comfy with, but once I found that oil I would stick with it.



BTW, I have run Rotella for 75,000 in my truck and I still regularly get 21+ MPG on the highway with the AC on.

 

[Jeff H]

I get about 20-21 mpg with Rotella. It doesn't get much better than that.

 

[pwr2tow]

With modern day oils and the additive packages they use I highly doubt switching to any oil will increase or decrease fuel mileage.



I have used Rottela T 15-40, Pennzoil 15-40, Delo 400 15-40, Rottela T 10-30, Mobil Delvac synthetic 5-40, Rottela T synthetic 5-40, all in this truck in less than 40,000 miles trying to find something that will give good pump up ability in cold climates, I have since stuck with the Mobil Delvac 1 synthetic 5-40 for the last 20,000 miles due to the cold climates up here. I use it year around with extended drains and filter changes every 3,000 miles religiously.



Switching back and forth has had no apparent harmful effects, still does not burn oil, even towing.



I gained zero mileage switching from dino oil to synthetic in the crankcase, differential, power steering.



The myth of increased fuel mileage (in my belief) is of past years when oil was not refined as well as it is today.



These are my findings, other may have different results.



Ron

 

[Hohn]

Hmm. Most of the guys I have heard that report the really high mileage (25+) also use Rotella.



My neighbor has an '01 ETH with 186K on it already, all on Rotella. He usually gets 22-23 empty on the HWY, but has gotten 26 under some circumstances (mostly downhill, good tailwind, etc).



His is a 2wd.



I am using a syn because it protect better in extreme hot and cold. Cold, for the WY winter, and HOT for the turbo.



I recently switched from the Redline 15-40 to the Valvoline Premium blue extreme 5-40. We'll see if there's any difference. That Redline is REALLY good stuff if you are willing to pay for it...



Justin