Onan Generator oil

[Ron & Dee]

What type and weight of oil to use in Onan Generator?

Thanks,

Ron

[akadeadeye]

I posed this question one time to our RV tech and he said they use Rotella 15/40, the same as we use in the engine. He did say that we should probably use the Onan brand oil during the warranty period, but it really didn't matter.

Don

[bachler]

You need to be more specific We've had onans I used a good grade of 10X40 in them over 2000 trouble free hours.Have the onan 7.5K onan diesel Use Cheveron diesel, Or Shell or Mobil All diesel oil. I say the best you can do is get a multi grade Good oil you like put it in and that is the best;;

[Belgique]

I'm pretty sure there is a label on the cover that gives weights for different operating conditions. There is one on my 5.5.

[edgray]

Originally Posted by Ron & Dee

What type and weight of oil to use in Onan Generator?

Thanks,

Ron

Rather than taking advice from those of us who don't KNOW what genset you have.....I suggest you get the model and "spec letter" info off the label on yours and look here: Cummins Onan

I do know that gas and diesel units have a different oil requirerment. I use straight 30 HD in mine.
Ed

[Hikerdogs]

Originally Posted by Ron & Dee

What type and weight of oil to use in Onan Generator?

Thanks,

Ron

The Adventurer came with an Onan 5500 watt HGJAB generator. 15W-40 oil is recommended for temps 10*F to 100*F. You can use 30W iol if you are in areas where temps don't go below 32*F. For temps 0*F to 80*F you can use either 10W-30 or 10W-40. For temps of -20*F to 50*F 5W-30 is recommended.

All these specs are available from the operators manual available from the Cummins site at:

http://www.cumminsonan.com/manuals

They also have parts, service, and installation manuals. I have all of them, but the service manuals aren't of much use to the average consumer unless you have the recommended special tools. Several of the diagnostic trees rely on use of special tools. They assume the manuals will be used by people with those tools so they don't give many details on how to make problem diagnosis without them

[Ron & Dee]

Thanks for the reply.

I have the Onan 5.5 and I needed a quick oil change for an upcoming trip.

I think I'll go with the 30 weight heavy duty.

Ron

[FDchief]

If you haven't changed it yet, you might consider Shell Rotella 5W-40 synthetic which protects you from below 0-over 100*F. I don't know about you, but I run my generator in temps greater than 80*.

I am a fanatic about synthetics, and know that they work. I would use Mobil 1 10W-30 if I knew I was protected to 100*+. I have used the Rotella since new, and now have 300+ hours on it and she purrs like a kitten with no oil use between changes. Which is every spring.

[Grimesy]

My Onan dealer suggested I stay with the Onan 15/40 in my diesel. Said main problem is some oils tend to foam which is a no-no. Who knows, because I run mine almost continually because my wife needs an oxygen concentrator I followed his directions without problems. Do run Rotella in my Cummins.

Don

[Five2o]

I use 15-40W Walmart brand whatever they call it in my 10kw Onan...so far it likes it...my Jeep does too!