Ok folks, as the OP, I get to layout how I concluded this topic.
Remember I am a person with ZERO experience changing any oil in a RV Generator. But, I do have a 9 year old Chinese made Sinemate 2500 Portable Generator that I will go toe to toe with ANY Honda owner. The key to generators is keeping carburetors clean and a good oil changed often
![offtopic](https://www.winnieowners.com/forums/images/smilies/offtopic.gif)
.
Here is how I concluded.
While the Rotella 15w -40 will work and most will never see any issues, it was clear to me it did not have any gasoline API specifications
Since I was determined to find a oil that 15w -40 to support ambient temperatures to 100F, the 30 weight oil options were excluded.
Since Synthetics were not recommended by Cummins Onan and due to the fact that they cost more, all Synthetic options were excluded.
Since all 15w -40 oils are compatible with Diesel engines, I only viewed options that were compatible with Diesel & Gasoline. Gasoline API specification is SN
I was left with only 3 options.
1. OnaMax 15w -40 as it is OEM, but at $17/quart I did not wish to support their complex scheme to rip off customers trying to do the right thing or simply don't know any better.
2. Wal Mart's Super Tech 15w - 40 it is by far the cheapest, but something about putting Super Tech in my 5500 did not resonate.
3.
Chevron Delo 400 15w -40 it came at a very economical price, rated for Diesel & Gasoline, Chevron brand name and the SN API Specification.
So I have picked up a gallon of the
Chevron Delo 400 15w -40
and intend to change the oil this weekend when I receive my Onan Oil Filter.