Originally Posted by ilmor
Do you know that your oil level was full before you started?
I see you don't have a manual. I don't either LOL. Try going to the Onan (I assume you have) website and downloading the manual, it's probably there. You should use whatever oil they recommend, especially while under warranty.
The manual is on a CD disk and the entire packet should have been wired to the Onan Generator. located under a cover on your Motor Home.. did you by chance ever open that cover to see if anything may have been hiding there.
As an owner it is your responsibility to do general maintenance on your motorhome, unless of course you prefer dropping it off at your dealership and letting it sit there for only god knows how long before they even get a chance to look at it.