Community Forums

BadBoy · 05-22-2016, 10:47 PM

I have perhaps a "dumb" question. I'm just in the midst of doing my oil changes.

My father in law gave me 3/4 gallon of Formula 1 5w50 synthetic oil. I was thinking of using it for my Onan Marquis 5500 generator which is on my 99 Southwind (gasser).

Does anyone know any positives or negatives to using this oil in my generator? I'm in BC thus the temps don't get too hot or too cold. Although we are doing a trip to California in July so we will be running the genny lots for AC.

I always use synthetic anyway, I'm just looking for details/opinions on the weight (good/bad?).

Thanks,

Name: Jason
(99 Fleetwood Southwind 32v)

MrTrouble · 05-25-2016, 11:02 AM

Quote:

Originally Posted by BadBoy

I have perhaps a "dumb" question. I'm just in the midst of doing my oil changes.

My father in law gave me 3/4 gallon of Formula 1 5w50 synthetic oil. I was thinking of using it for my Onan Marquis 5500 generator which is on my 99 Southwind (gasser).

Does anyone know any positives or negatives to using this oil in my generator? I'm in BC thus the temps don't get too hot or too cold. Although we are doing a trip to California in July so we will be running the genny lots for AC.

I always use synthetic anyway, I'm just looking for details/opinions on the weight (good/bad?).

Thanks,

Name: Jason
(99 Fleetwood Southwind 32v)

Hey there,

When I bought my coach about 6 months ago, I changed everything on my genset but the carburetor. When I spoke to Onan, to verify part numbers, they told me specifically to use conventional oil, and not synthetic, which I did. Now, I'm no mechanical engineer, and I don't know if that was a "by the book" answer or whether there is truly reason to use conventional oil, but that is what was said to me by Onan.

Hope that helps some...

Juan

mfire1339 · 05-25-2016, 11:09 AM

My 2004 Onan 5500 has had 10/30 mobile one in it for 9 years. Err, not the same oil. I change it annually.

Mike

vsheetz · 05-25-2016, 12:40 PM

10-30 mobile 1 here in Onan 5500 in our PA. As for using the oil you have on hand, I dunno. Myself probably would not as while the risk is probably low, the gain is also low...

Fred and Bonnie · 05-25-2016, 04:31 PM

When I tried synthetic oil, used oil and blew smoke, went back to Onan Oil, problem solved.

Fred

BadBoy · 05-26-2016, 08:27 AM

Thanks all for your replies. I decided to go with it. I'm not particularly concerned about the synthetic as I have literally ALWAYS run it from the day I bought it.

I was more concerned about the weight 5w50. I did a little reading and several people regularly use that in their small engines for added protection.

I'll watch it and drain it if it's not running right. I regularly change my oil and filter. Over 700 hours on the genny so far!

Name: Jason
(99 Fleetwood Southwind 32v)

rottenkid · 05-26-2016, 04:20 PM

Have you checked the handbook. I would not recommend that oil. It is for colder weather. Check the handbook

http://power.cummins.com/sites/defau.../F-1123-EN.pdf