Best Onan Oil

[Blaze56]

Originally Posted by maddogrdhg

Have 5500 gas onan. Has about 200 hrs. Been running Dino oil and decided due to how hot these get to switch to Full Synthetic Amsoil 15-30 motorcycle oil. It now smokes on startup. Lasts about 2-3 months minutes tops. Haven’t run long enough to see if using much oil. Looking for experiences of others.

I see this online at the Cummins Onan Store

ONAMAX 15W40, $6.08 qt or ONAMAX SAE30 $6.57 qt plus shipping

Online Cummins Onan generator parts and manuals, you'll need to know the model and spec of your generator set. If you don't already know this information, the steps below will help you identify it.

1. Can you read the information on the nameplate?

The model and spec of the set are indicated on the nameplate. The spec is the letter at the very end of the model information. Depending on the age of your set, the spec may or may not be clearly identified for you.
Here is an example of a nameplate for a model KY spec K: 4KY-26100K (my Spec was R but it was not listed)

https://www.cumminsonanstore.com
https://www.cumminsonanstore.com/howto/

[sgrol]

From my Cummins Onan RV Generator Handbook -

Q: Can I use synthetic oil in my generator?
A: People use synthetic oils because the general opinion is that they can be left
in the engine longer than regular oil. However, if you decide to use synthetic oil
in your generator the maintenance time intervals given in the operator manuals
must still be followed.