which one shell rotella T1 SAE 30 OR T4 15W40 diesel oil ?

[xxhat]

Would appreciate any comments on which of the shell rotella diesel oils do I
use for my Kubota betamarine 14 engine.


Manufacturer recommends CF grade but that is now OBSOLETE.


Both above oils have CF-4 grade.

[Pete7]

This is worth a read on the back ground to the problem.

Oil for yacht engines – Cox Engineering

The good news is it doesn't have to be Rotella, any good oil to a later suitable spec will do, after all at its heart is a little industrial engine used the world over.

Pete

[NYSail]

I stick with the 15w40. I am in northeast and climate is moderate here. I use shell Rotella oils and coolant in my yanmar.......

Greg

[Wotname]

Originally Posted by xxhat

Would appreciate any comments on which of the shell rotella diesel oils do I
use for my Kubota betamarine 14 engine.


Manufacturer recommends CF grade but that is now OBSOLETE.


Both above oils have CF-4 grade.

If I had to chose between these two oils, I would need to know the expected ambient temperature so what is your expected ambient temperature????

[xxhat]

I am in southern california where it never rains

[sailorboy1]

it probably doesn't matter at all, but I would and do use the 15/40

[NYSail]

I use SAE 30 in my transmission....

[ranger58sb]

Kubota/Beta may make further recommendations about expected temperature ranges, so check for that.

I think 15W40 is the one for warmer temps (like where you are) and for wider temp ranges... but I may have it backwards.

-Chris

[Suijin]

I would just call Stanley at Beta Marine in NC and ask him. He spends all day customizing/testing/prepping them for delivery and is probably your best source of information.

[Greg Mason]

I am on the west coast of Canada, and my Cummins uses 15/40 and SAE 30 for the transmission.

[SV Bacchus]

I use 15W40, based in FL. The Yanmar transmission calls for 30W. I've stayed with Shell Rotella.

[bigreelsc]

We are located in Florida and have used Rotella 40 in all our engines Detroits and Phasor generator and the tech says that they display minimal wear for their age.

[ferrailleur]

everyone use Rotella 15W40.... I use it n my trucks, I use it on my boat....
It's around $13 a gallon at WalMart.

[tstano]

Originally Posted by ferrailleur

everyone use Rotella 15W40.... I use it n my trucks, I use it on my boat....
It's around $13 a gallon at WalMart.

Same here, once I goofed and bought the synthetic, I think the boat forgave me.

[a64pilot]

Either is OK, Although the straight weight 30 is likely better.
Why? Because you have no need of a multi viscosity oil. The reason you have no need of it is because your not cranking your engine at below freezing temperatures and pretty quickly running it at high way speeds, where you oil temp is above 200. Which is exactly the average car, not a high performance car, say a Toyota Corolla.
Your starting your engine in short sleeve weather most likely and your oil temp likely never gets close to 175, much less over 200.

Just for goodness sakes don’t run a synthetic, or you will be like millions of Yacht owners who go through their whole crankcase of oil in a day.
“said with more than a little sarcasm”

The key, in my opinion is to change oil frequently, whether I’d be a straight weight oil or a multi viscosity oil.
By the way, the first thing to break down in oil is usually it’s VI package, that is the viscosity improver package.
But your unlikely to be breaking down your oil anyway, even if you have a turbo, although a turbo by itself due to the center section temps is likely harder on the oil than the engine. Unless your turbo is water cooled, then likely not.
So in truth the answer as always is it depends.