S rated oil instead of C rated oil for a diesel engine

[callistov42]

I am in the Caribbean. I can't find any C rated motor oil and my generator needs an oil change. I can find Casteroil S rated oil. Won't it be OK for a couple of hundred hours?

[a64pilot]

If it’s the proper viscosity, it’s better than not changing the oil.
Often times the difference is that some Diesel oils have additives that will kill Oxygen sensors and other gasoline engine pollution controls
https://www.machinerylubrication.com...il-differences.

Truth is that most of the times they way most of us operate our engines, really isn’t considered severe at all, assuming you don’t pull the guts out your generator continually as in always making max current, you will be fine.
However I would change back to Diesel rated oil when it becomes available, just because you should.

Many, many good Diesel engine oils can actually be used in spark ignition engines too though.

[MarkSF]

Used to be that most oils were rated S and C. Now they're getting more and more specialised, that seems not to be the case. I think it's the SN specification that did it, some of the requirements are somewhat orthogonal to those of diesels.

Can't you get Chevron Delo? I thought that stuff was ubiquitous. It's still rated SN as well as for diesels btw.

[a64pilot]

The better Shell Rotella T6 is also a universal oil usable in all engines, ( I have run it in our cars for years) however it’s not real widely available outside of the US, best to carry your own supply when you can.
I will probably go back to it, just because with one oil I can cover the outboard, generator, main engine and Honda, although regular Rotella would be fine too.
Many people who have spark ignition motors but run them very hard use Diesel oil, like the dirt bike crowd, because from a shear and stability point of view Diesel oil is more stable, and or better for wear prevention.
Like the article said, it’s the additive package in some Diesel oils like zinc that is also used as a TBN improver as well as anti wear, will poison some catalysts, but if your Honda generator doesn’t have those catalysists (it doesn’t) Diesel oil is fine for them, same in my opinion for a four stroke outboard.

[Jammer]

Originally Posted by callistov42

I am in the Caribbean. I can't find any C rated motor oil and my generator needs an oil change. I can find Casteroil S rated oil. Won't it be OK for a couple of hundred hours?

The S rated oils don't have the correct dispersant and will eventually lead to damage in diesel engines.


You should be able to find C rated oils anywhere diesel engines are serviced, truck, marine, off-highway equipment.

[FPNC]

Originally Posted by a64pilot

The better Shell Rotella T6 is also a universal oil usable in all engines, ( I have run it in our cars for years) however it’s not real widely available outside of the US,

Look for Shell Rimula 15W-40 outside the US.