Generator oil change/sythentic ?

Newer Onans use splash lubrication, which is harder on oil than pressurized systems. I'd run dino oil for the first couple oil changes so the generator engine is broken in, then switch to synthetic.

Whatever name brand dino oil is on sale and of the correct weight will do great.

I use straight 30W Royal Purple, because I like the protection it provides at warmer temperatures. It's not good for below 0 temps though. My generator has over 500 hours on it an runs really well.

Just because it is a synthetic oil does not mean it's an extended drain oil.
I have used Amsoil 10W30/SAE 30 Synthetic for 4 stroke engines for a number of years. It is what I use in my generator, John Deere garden tractor, Honda lawn mower, and Kymco scooter.. Your Onan is in a confined space and it does get pretty warm. A quality synthetic will offer better thremal breakdown protection As well as better protection during cold weather, too. I don't know what weight your Onan uses, but they also make a 10W40 designed for 4 stroke engines.

Yes.
Longer periods between oil changes.

eabc5454 wrote:
Hello:

I have an Onan QG4000 generator that is due for its first oil change (20 hours). I have the owner's manual, and while it lists the correct oil based choices on temperature, it has no discussion on synthetic oil. I actually called Onan, and they said the owner's manual tells you what oil to use. Well, yes, it tells me viscosity, but not whether synthetics are OK.

So, here are my questions for those of you who are far more knowledgable than I:

Is it OK to use sythetic oil? If so, is there any benefit in doing so?

Thanks!

I actually had an Onan rep. at one of the big FMCA rally's recommend using a synthetic (mobile 1) in the correct viscosity... but I am sure either is fine...

Here's a previous post on using Synthetic Oil in Onan Generators.
Maybe this will give you an answer.

Good idea on the Onan oil, but I didn't want to order it online and pay shipping - the closest dealer is over an hour away, so driving there didn't make sense either.

I guess I'll just use regular oil.

Just plain old Dino for me.

I've always used Onan's oil for generators.

It seems like that should meet their requirements.