Onan HGJAB generator oil?

[Michael J.]

A couple questions:
I have a Onan HGJAB 7k GAS generator. And I am going crazy trying to figure out what oil to use. I keep hearing of people using Rotella, but this is diesel oil and not SM, SN or SP, As conventional oil is getting harder and harder to find. What Type, Make and grade oil are you using?

 

[Rollin Ollen]

A couple questions:
I have a Onan HGJAB 7k GAS generator. And I am going crazy trying to figure out what oil to use. I keep hearing of people using Rotella, but this is diesel oil and not SM, SN or SP, As conventional oil is getting harder and harder to find. What Type, Make and grade oil are you using?

Years ago when I had Cummins service our generator, I had them use Mobile1. They didn't seem to have an issue installing it.

Darrell

 

[Joe Hogan]

There are tune up kits on Amazon for these generators. This is what I ahve used in the past.

https://www.amazon.com/onan-5500-oil-change-kit/s?k=onan+5500+oil+change+kit

 

[jbh]

I've used plain Rotella T4 15W-40, Mobil semi-synthetic 15W-40, Rotella T6 full synthetic 15W-40 and Royal Purple 30W full synthetic in my 30-year-old Onan propane generator, all with no excessive oil usage, leaks or other problems. I like to use synthetic in the air-cooled generator in hot climates.

I've read that diesel oil is a problem only for cars because it messes up the cat convertor.

 

[Michael J.]

What about this oil.
https://www.tractorsupply.com/tsc/product/valvoline-cummins-premium-blue-diesel-engine-oil-1-gal
The manual does not state 15W-40 however it does state 10W-40 and straight 30W oil

 

[jaydee325]

A couple questions:
I have a Onan HGJAB 7k GAS generator. And I am going crazy trying to figure out what oil to use. I keep hearing of people using Rotella, but this is diesel oil and not SM, SN or SP, As conventional oil is getting harder and harder to find. What Type, Make and grade oil are you using?

What is the viscosity and service spec as specified in your manual?

 

[Michael J.]

What is the viscosity and service spec as specified in your manual?

Since you requested:

 

[jaydee325]

Armed with that info. Go to your local big box auto emporium or other big box store that stocks oil and find a 15W40 (more common these days) in a SM or better grade. Brand does not matter. Standard or synthetic, doesn't matter. Standard if you are trying to keep cost down.

 

[AbdRahim]

Cummins 3265336 Onan SAE 15W-40 Oil - 1 Quart Quantity 2