Delo 15-40 Or Synthetic

[chp007kd40]

What is the most preferred oil for 07 cummins 8.9 and onan 7.5. I have been using Chevron Delo and didn't give synthetics much thought.

Should I be considering it?

David

[wolfe10]

David,

Not sure there is a simple answer to your question.

Does Delo 400 15-40 meet Cummins standards, YES.

Can you get extended change intervals by using a synthetic? No, not according to Cummins.

Will use of a synthetic in your Cummins or diesel generator extend the engines useful life in an RV application? VERY doubtful-- the number of oil related failures is close to zero.

Are synthetic oils better? Probably.

Clearly, if you live and use the engines in extreme temperatures (particularly cold temperatures) the synthetics have more appeal.

Now, my opinion: I have used synthetics in all my gasoline powered vehicles for over 30 years. I do not use synthetics in my diesels over that same time period. Never had an oil-related failure on either-- better yet, never had an engine failure yet.

[chp007kd40]

Great explanation Brett!! Thank you, David

[desertdeals69]

I have been using synthetic Rotella T6 for a number of years and have run for more miles than with conventional oil. I have the oil analyzed at proper intervals and go by the results as to when to change. I have a Cummins ISB 5.9 with 140k miles.

[five]

What Brett said, except I don't use synthetics in anything.

[sashton]

I had my Freightliner/Cat service center advise against synthetics in Diesel engines. He said that if water ever got into the oil for some reason it complicated the clean-up because water mixed with sythetic oils turns into a gooey "glue" that was difficult to clean out of oil passages and intercoolers. He advised me to stick with straight Rotella.

Skip

[desertdeals69]

Water will emusify any kind of oil. I have dealt with water in the crankcase in boat singings for 50 years and 100s of engines. Not a big deal, flush out with diesel in the crankcase.