Home Forums Hunting & Shooting Hunter's Campfire Best diesel engine oil

I have used Shell Rotella T 15w40 since about 1985. Used Delo 400 for a short time in my first diesel pickup but quickly switched to Rotella T because of better availability. Sold my last diesel pickup this year but still have a diesel Kubota tractor and diesel Kubota RTV X900 UTV.

Right after changing oil in the UTV the first time using Rotella T, I noticed a smell like I had spilled some oil on the exhaust manifold. I never could find any and in a few hours, the smell went away. Later, I found a comment on the internet about the smell of new Rotella T. Last time I changed the UTV oil, I used Chevron full synthetic 5w40. There was no smell at all. I've never noticed this odor with any tractor or pickup.

Has anybody experienced this smell ?

What is your favorite diesel oil, especially in tractors? I'm considering Mobil Delvac, Chevron Delo 400 and Rotella T.

I use Mobil Delvac in one diesel tractor, and Rotella in the other. No problems with either. The only reason I'm using the Rotella is because that's what the previous owner used, and I didn't want to switch.

Conoco 15-40

Never owned anything diesel, if I did I would run Rotella.
$22 a jug at Walmart, available at any Walmart(everywhere) and a quality product.

I run T6 in my BMW 325i.

I used to worry about switching oil brands but don't now. Any odor with the Rotella T? I think it has to be coming from the crankcase venting. Not sure either of my engines even vent to the atmosphere anymore. That is probably against some Federal regulation.

Well, Conoco wasn't on my radar. I'd rather stick with something I can order from Wally World. Does Conoco make their own oil?

Do you ever use 10w30 up there in the cold? My Kubota tractor says 15w40 down to 14, then 10w30. We get below zero here some but most starts are probably above 14 degrees.
The tractor has a block heater and I plug it in if it's below freezing or so. Still, that doesn't warm the oil.

I put synthetic in the Ute because it doesn't have a block heater and gets started in the cold way more than the tractor.

if you got a block heater in the Kubota 15w40 dino will suffice ...I prefer Delvac


I use 5w40 synthetic in anything that gets started during the winter in these parts

Rotella in my JD x495, it's the only diesel I own.

I used Rotella T6 for a long time with good results. The last few oil changes I've used the Chevron 5w40 synthetic and noticed no change. It's a coupla bucks cheaper per gallon and available at WM.

Use to run Mobil One but recently switched everything to Schaeffer's..

Haven't gone with 10-30 yet.

Did try some Rotella last winter. It was 5-40 or some such thing.

Rotella.

Delvac would suit me, but availability isn't good.

Honestly, I would feel safe with any oil properly rated,
But don't have to do that.



Now a question.
How could any one person not running a fleet of dozens of constant
running engines honestly judge?


And, does anyone really think in today's connected/litigious society,
That any company could get away with substandard oil?

I use Rotella T 15w-40 in my Dodge Cummins. My Kubota tractor calls for 10w-30, and I use Rotella in that too, harder to find though.

Years ago Rotella T was kind of famous for an oil stink right after oil change, but they changed something to stop it.

Ran Rotella T in the Volvo L90 loaders when I was working. The highest hours for any of the five loaders, 32000 hours using Rotella T. She'll oil wanted to use our machines in advertisements, we declined! The other loaders averaged 26000 hours before rebuilding. Prior to using Rotella T 20000 hours was the longest we got! That was changing oil weekly! That said my experience with other oils is limited. Each oil change, from each machine was sampled and sent to the shell lab, to be analyzed! As the machines got older the samples gave great information about what was happening to the machines! All oil companies make good oil, and not many run there machines 24 hours a day, six days a week! Delo is what I run in my duramax, because that's what the prior owner used. The smell I never noticed from Rotella T!

I have used Rotella T6 for several years and never noticed any weird smell. I have not bought it in about 1 yr however. I use the T6 all the time in My Duramax and it is easy to find.

Shell Rotella or Mobil Delvac 1. Delvac 1 is “not” easy to find! memtb

What was the previous oil used? How many hours between oil changes on Rotella T?

Good info, thanks.

I use Rotella in my Dodge Cummins

One other question....My Kubota M6-131 calls for the first oil change at 50 hours. I've done that and now have about 140 hours total time. That's in a little over 2 years. Next change is due at 400 hours. Nothing is said about time. That would be years from now. How long, time wise, would you go between oil changes?

Not a bad idea to go at least yearly.


The diesel today has low sulfur, but its still a good idea to get the water out of the crankcase once in a while.