Onan Oil Or

[bruce91]

Looking at previous posts many have used mobil 1 in their gas gensets. This got me to thinking about the oil in my air cooled motorcycle that has a different formulation for air cooled versus liquid cooled.

Our gas generators are air cooled so wondering if that motorcycle thinking would apply.

I'd like some opinions.

[WILDEBILL308]

Originally Posted by bruce91

Looking at previous posts many have used mobil 1 in their gas gensets. This got me to thinking about the oil in my air cooled motorcycle that has a different formulation for air cooled versus liquid cooled.

Our gas generators are air cooled so wondering if that motorcycle thinking would apply.

I'd like some opinions.

I have run Mobil 1 in all my gas generators. I would go to Mobil 1.com and see what they recommend. They have a hotline where you can call and ask them.
Bill

[Beau388]

Originally Posted by bruce91

Looking at previous posts many have used mobil 1 in their gas gensets. This got me to thinking about the oil in my air cooled motorcycle that has a different formulation for air cooled versus liquid cooled.

Our gas generators are air cooled so wondering if that motorcycle thinking would apply.

I'd like some opinions.

Unless your Onan has a wet clutch like your motorcycle, I wouldn't use the same oil. You could use the same oil you use in your Corvair or aircooled VW.

[Waiter21]

From the Onan manual:
Use API Class SG or SH oil (also SG/CD, SG/CE, SH/CD or SH/CE) having an SAE viscosity grade appropriate for the expected temperatures.

If your motorcycle oil meets this specification, then its acceptable to use in the Onan.

The absolute best oil in the world to use in your Onan, is the oil that meets their specification and lets you sleep at night. I use regular ole dead dinosaur 5w30 in mine.

[Waiter21]

Not sure what manual you have, but my manual says:

Yours may be a newer manual. Mine is for my 5500.

http://1999southwind.com/DOWNLOAD/55...on_Mmanual.pdf

API SJ is backward compatible with any API designation SA thru SJ. The 5w30 I use from Walmart ($12 for 5 qt jug) has an API SN rating. I'm not sure I could find any SA unless someone had a case of it sitting in their garage for 15 years :-)

[okcnewbie]

I've already switched to M1 syn 15W50 in my generator and motorcycle. Here's why. (actually it's because it's cheaper and it works)

Read post #5
Anyone using Synthetic Oil in Honda Gen ? - Airstream Forums

[Hit_the_Rhod]

Just don't use any oil that has graphic as an additive in any engine/equipment that has a wet clutch (as previously stated) as the graphite will impregnate the clutch disks and they will start to slip extremely well! Bought an immaculate Honda CB900 with 2500 miles on it for 25% blue book because the original owner had changed over to Mobil 1 graphite oil . . . clutch started to slip, he replace the clutch, new clutch started to slip. Honda dealership told him that the clutch shaft must be bent to cause new clutches to go "bad" in such a hurry! Note: The Honda dealership never worked on the motorcycle, just gave him advice sight unseen . . . Owner was replacing oil and clutches on his own. For the wrong reasons, he was caused the problem himself.

Took multiple oil changes and two clutches, two gaskets to get all of the graphic residue out of that engine/transmission/clutch! Then 20k miles over the next 4 or 5 years with narry a problem . . . God I miss that bike!

[Randalpho]

Originally Posted by Waiter21

Yours may be a newer manual. Mine is for my 5500.

http://1999southwind.com/DOWNLOAD/55...on_Mmanual.pdf

API SJ is backward compatible with any API designation SA thru SJ. The 5w30 I use from Walmart ($12 for 5 qt jug) has an API SN rating. I'm not sure I could find any SA unless someone had a case of it sitting in their garage for 15 years :-)

According to page 5 - 5W30 is only good to 50° F ambient temperature

[olcarguy]

If I can't find Harly oil for my motorcycle the manual call for any se class of dino diesel oil. If it's good enough for an air cooled bike should be good for air cooled genset.

[Gary RVRoamer]

I don't think the oil knows whether the engine is air cooled or water cooled. It's just "cool". Use the oil viscosity and API class that Onan recommends for your genset. Not necessarily the Onan brand - they don't make oil anyway. Just any brand that meets the spec.

You can use a synthetic if you like (e.g. the Mobil 1), or good oil Dino oil.

Motorcycle engines do have different characteristics than many other types and may have some special lubrication needs, but it's not simply air vs water cooling.

[Waiter21]

According to page 5 - 5W30 is only good to 50° F ambient temperature

We run anywhere from -20 to 120 degF. All my bases are covered. 5w30 is a good compromise for this wide temperature range.

Besides, it keeps my inventory simple, I use this same oil in my cars, lawnmower, snow plow, truck, tractor, etc.

I think the "5" is kind of where I'm at when I first start the engine and its cold (oil is thin). The "30" is kind of where its at when the engine gets up to operating temperature.

[bruce91]

Originally Posted by okcnewbie

I've already switched to M1 syn 15W50 in my generator and motorcycle. Here's why. (actually it's because it's cheaper and it works)

Read post #5
Anyone using Synthetic Oil in Honda Gen ? - Airstream Forums

Post #5 from above link, very good information. Thank you.

Just bought 2 122-0836 onan filters at my local RV parts store (ouch$$) and mobil 1 5qt 15w/50 at walmart for $22.88.

I had pulled the filter to see what was in there and the oil looked kinda dirty. Not knowing it's history as it's new to me i'm going to change the oil and filter then after a few hours run time do it again. I know then i'll be good for my annual service.

As for my Harleys ( '85 FXRS & 2010 ultra Classic ) i'll stick with red line that i've been using for ever.

[trx430ex]

Has anyone used a fan powered oil cooler to help the Onan out? It seems our extreme temps are getting even more extreme. Come out the drain, go In the fill, would also add volume of oil. Wait, at the base of the fill is another in.

You cool the oil, it may solve a multitude of issues.

[trx430ex]

Anyone ever point a ir temp meter at the Onan to see if it is operating at spec temperature? Question it, the best oil in the world will not save you from thermal breakdown in original design.