Onan generator oil

[HawkTX]

I have an Onan QG 2800 gas generator on my 2019 Coachman CrossFit. I need to do an oil change and cannot find what oil it uses in the paperwork. Any recommendations?

[mloganusda]

5.5.2 Engine Oil Recommendations • Use API (American, Petroleum Institute) performance.Class-Sf SJi or SG engine oil, which may be in combination with performance Class CH-4, CG-4 or CF-4 (for example: SJ/CH4).
• Look for the SAE (Society of Automotive Engineers) viscosity grade. Choose the viscosity grade appropriate for the ambient temperatures expected until the next scheduled oil change.
" Single-grade' SAE 30 oil is preferable when temperatures are consistently above freezing. Multigrade oils are better when wide temperature variations are expected.
TABLE 10. Oil VISCOSITY VS. TEMPERATURE
EXPECTED AMBIENT Temperature's
0°C (32*F) and higher= 30W OnaMax
-12 to 38 °C (10 to 100*F) 15W-40W (OnaMax
-18* to 27 °C (0 to 80*F) 1OW-30 10W-40W
-28 to 10 °C (-20 to 50*F, 5W-30W

MLogan
2017 Trend
2800 KW Generator
Smyrna, TN

[HawkTX]

Originally Posted by mloganusda

5.5.2 Engine Oil Recommendations • Use API (American, Petroleum Institute) performance.Class-Sf SJi or SG engine oil, which may be in combination with performance Class CH-4, CG-4 or CF-4 (for example: SJ/CH4).
• Look for the SAE (Society of Automotive Engineers) viscosity grade. Choose the viscosity grade appropriate for the ambient temperatures expected until the next scheduled oil change.
" Single-grade' SAE 30 oil is preferable when temperatures are consistently above freezing. Multigrade oils are better when wide temperature variations are expected.
TABLE 10. Oil VISCOSITY VS. TEMPERATURE
EXPECTED AMBIENT Temperature's
0°C (32*F) and higher= 30W OnaMax
-12 to 38 °C (10 to 100*F) 15W-40W (OnaMax
-18* to 27 °C (0 to 80*F) 1OW-30 10W-40W
-28 to 10 °C (-20 to 50*F, 5W-30W

MLogan
2017 Trend
2800 KW Generator
Smyrna, TN

Thank you!!! Exactly what I was looking for.

[mloganusda]

Here is a PDF file on generator maintenance.

MLogan
2017 Trend
Smyrna, TN

[HawkTX]

Originally Posted by mloganusda

Here is a PDF file on generator maintenance.

MLogan
2017 Trend
Smyrna, TN

Appreciate it. For some reason this was missing in my owners bag that came with my unit. All it had was in onan generator DVD.

[Coachmen Crossfit owner]

they sell it at Camping world. 15 W 40 Onan brand. also purchase the screw on the bottle oil filler hand pump. It makes it so much easier.

[silver bullet]

Call Cummins. They are the registered manufacturer of these generators.

[rowiebowie]

I researched generator oil and it seems the OnanMax 15W-40 is conventional oil. I'd like to find a suitable full synthetic. I found a few straight 30W oils by Aimsoil and Royal Purple. So they might be my second pick. But . . .

Has Anyone found a 15w-40 Full Synthetic that is not for Diesel or for High Mileage motors?

I did find this one that lists "high zinc". Is that good or bad for an air-cooled onan generator? https://www.amazon.com/Brad-Penn-Oil...0&sr=8-66&th=1

How do diesel oils differ and are they ok for my onan?

[booster]

Originally Posted by rowiebowie

I researched generator oil and it seems the OnanMax 15W-40 is conventional oil. I'd like to find a suitable full synthetic. I found a few straight 30W oils by Aimsoil and Royal Purple. So they might be my second pick. But . . .

Has Anyone found a 15w-40 Full Synthetic that is not for Diesel or for High Mileage motors?

I did find this one that lists "high zinc". Is that good or bad for an air-cooled onan generator? https://www.amazon.com/Brad-Penn-Oil...0&sr=8-66&th=1

How do diesel oils differ and are they ok for my onan?

IMO, Redline probably makes the best air cooled engine oil around. PAO 5 full synthetic so is very, very, good against heat. They also use the full zinc additive package in their oils, and that is why you won't see an SM or SN oil in Redline, only "equivalent" oils. You want that additive package on any non rollerized engine, like most air cooled are.


We ran the 15W40 Redline in our Onan when we had it, and have for many years in the lawn tractor. It seems to stay in grade better than any other and the engines run cooler with it. The 15W40 crotch rocket motorcycle oil is a very good one, but even there regular 15W40 is excellent.

[rowiebowie]

Originally Posted by booster

IMO, Redline probably makes the best air cooled engine oil around. PAO 5 full synthetic so is very, very, good against heat. They also use the full zinc additive package in their oils, and that is why you won't see an SM or SN oil in Redline, only "equivalent" oils. You want that additive package on any non rollerized engine, like most air cooled are.


We ran the 15W40 Redline in our Onan when we had it, and have for many years in the lawn tractor. It seems to stay in grade better than any other and the engines run cooler with it. The 15W40 crotch rocket motorcycle oil is a very good one, but even there regular 15W40 is excellent.

I can only find 15w-40 Redline oil (and most others) in diesel or "racing" oil which states it is not legal for the street. Would racing oil be good for the generator since it is not a street vehicle?

[booster]

Originally Posted by rowiebowie

I can only find 15w-40 Redline oil (and most others) in diesel or "racing" oil which states it is not legal for the street. Would racing oil be good for the generator since it is not a street vehicle?

Onan Racing, that would be a sight. First one to stop wins? or loses?


Wow, all new website and rearranged product line at Redline. Hadn't seen that. Of particular interest is that the finally added a "manufacturer" approved line of oil, so no have the warranty keeping products available. They have resisted doing that for many years, siting the high costs of the certified approval testing, even though the products easily would pass once they reduced the zinc. I will have to check in a Bob is the Oil Guy to see what they are saying about it.


They also have reduced a bit of the 15W40 rating line to diesel only and settled in on the 10W40 for the non diesel oils in the non racing lines. The Performance oil line would be good as it has full additive package, as would the sport motorcycle oil in the Powersports line. If you are stuck on 15W40, the performance line diesel oil would also be OK, you just have some extra additives like soot absorbers in it. I would not use the OEM line as they have the required change to the additive package to preserve catalytic converters.



We use the Redline Performance 5W30 in our Chevy when we are going on a long trip where mileage is on the far top edge of how far we would go without changing and the weather hot, speeds high, and lots of long climbs. Around home where it is cooler, no mountains, and we can change it more often, we use the half the cost Mobil1. For a single quart in the Onan, extra cost isn't really much of a factor.



I put in a message to Redline to try to get some confirmation of what design all the series are, as the site is kind of confusing on the SM/SN thing.

[rowiebowie]

I use Mobil 1 5w-30 in the 6.0L. Try to change it sooner than the dash "Oil Life" monitor shows if only for the fact that hauling around a 9,000lb van is roughly equivalent to "towing" with all that extra weight. But we've been on trips where we went into the last 10% and changed oil after we got home to save an extra stop while on the road.

The generator motor is a far different thing. Air-cooled, no oil filter, no fancy fuel injection, runs continuously at 3600 rpm, etc. It may benefit from "high zinc" or other formulations that are different from requirements of modern car engines. I just don't know.

As you state, the extra cost of a single quart of oil once a year (we mainly just exercise our Onan) is a negligible cost. And there's always the chance we'll run it hard if the need arises on road or back home during a Hurricane power outage since my stalling problem has vanished with more use. So this is why I'm searching for a premium synthetic oil, preferably in the 15w-40 weight.

[mkguitar]

Originally Posted by rowiebowie

Has Anyone found a 15w-40 Full Synthetic that is not for Diesel or for High Mileage motors?

You could look at oils made for motorcycles
there are many many options every major oil and motorcycle brand has synth multigrades available


( motorcycles forums have oil threads longer than the internet- there are no huge advantages to speciality, custom or niche manufacturers, red purple or other)
few motorcycle oils have API ratings






I am using the manufacturer spec'd type oil in my genny




I have a number of new and old motorcycles ( & other air cooled)



Some older and air cooled motors are made with wider tolerances which get tighter when the motor heats up and expands.

Synthetic oil may be prone to leaking past gaskets when parked- less likely to penetrate and swell paper type gaskets if used in that motor


you might find yourself with seeps and then changing back


BUT my 78 honda trail 90 is tight with the synthetic I tried in it...I did park it over a pan for the first few months


report back










mike

[SteveJ]

A genny oil thread. Cool. If looking for a 15w40 synthetic, Shell Rotella came out with it not too long ago. Likely available at Wally, and definitely at most Fleet/Farm stores.

[@Michael]

Originally Posted by mloganusda

5.5.2 Engine Oil Recommendations • Use API (American, Petroleum Institute) performance. Class-Sf SJi or SG engine oil, which may be in combination with performance Class CH-4, CG-4 or CF-4 (for example: SJ/CH4).

I have the same Crossfit/Onan setup. Non-diesel 15w-40 is hard to find. I ended up using Chevron Delos 15W-40 conventional oil. It's rated CJ-4/SM.

The only down side is that so little of it is sold around here that the local auto stores either were out, or had years-old stuff buried behind boxes of obsolete parts.

[booster]

I will throw in a bit of a disclaimer here on diesel oils, as they too have changed in recent years.


They used to be the choice of oil for older cars with non rollerized engines as they all had the high zinc additive package. That is no longer true as the newer versions have reduced similar to the gas engine oils. I haven't dug deeply into the specs and grades for the diesel oils, so I can't give the specific ratings you need or don't want to get the good additive package, though.


Unfortunately, the same thing has also happened to some motorcycle oils, which were always our first choice for the small engines like the lawn tractor, again with reduced zinc additive packages. I have not gone deeply into them either as we just went to Redline on everything like that, or added zinc additive. Thumper oil, aka 20w50, I am told can't change as the old air cooled engines need the high viscosity heavily zinc additive oil by design.


The manufacturers are very, very, very, reluctant to give actual zinc concentrations on anything other than the SM/SN, soon SP, oils as they know if they are getting that question, and they are using reduced zinc packages in all their non SM/SN oils (yes that is OK per backward compatibility laws) nobody will buy it.


Redline and Royal Purple are the only ones that I have found that will tell you much of anything. Amsoil are full of deception on that issue. I bought SL bottled oil for my old flat tappet Challenger V8 and it ate the rockers and pushrods. Fixed it, broke it in on Castrol dino oil and again put in the SL Amsoil. It did it again. Cost me nearly $3000 in parts to fix total. After much, and mean much, digging I found they had SM oil in the SL bottles to use up the bottles and it was totally OK with API because of backwards compatibility.


Anyone with hotrods when the reduced zinc packages showed up know how bad they were for older cars, and the oil suppliers insisted for at least a decade that all the cam and valve train failures had nothing to do with the oil changes to reduced zinc. Then they came out with "old car oil", "small engine oil" etc and touted how it would save the old engines. A bit hypocritical, I think.



You need to be very careful with old school rules these days, as a lot of them no longer apply.

[booster]

Originally Posted by @Michael

I have the same Crossfit/Onan setup. Non-diesel 15w-40 is hard to find. I ended up using Chevron Delos 15W-40 conventional oil. It's rated CJ-4/SM.

The only down side is that so little of it is sold around here that the local auto stores either were out, or had years-old stuff buried behind boxes of obsolete parts.

That oil appears to be double rated for gas and diesel, and the SM would indicate it is a reduced zinc additive package oil, so probably no better than a gas engine oil rated SM in regards to non rollerized engines.

[Deano]

This is the email I received in response to my question about using synthetic oil in the Onan 2800 generator.

Good morning! I’m sorry it’s taken me as long as it has to respond, I have tried to be as thorough with your request as I can.
I have checked with technicians, service supervisors, and even one of our DFSE’s (Distributor Field Service Engineer) and they all recommend NOT using synthetic oil in this application.
This model does not have a pressurized lubrication system (no oil pump) and therefore also does not have an oil filter.
Synthetic oils are heavily reliant on oil filtration to remove dirt and other impurities.

I have attached a copy of the Oil Recommendations from the Owner’s Manual for this model, which I feel you already have a copy of, (this is all I can find for this application).

Please let me know if you have any questions or if I can be of further assistance!

Thanks, Kevin

Kevin Pierce
Parts Manager
Military Sales Specialist
Cummins Power South, LLC
1915 W. Oakridge Drive
Albany, GA 31707
(229) 888-6210 ext 6214
(229) 883-1670 fax
(229) 376-5712 cell
Kevin.d.pierce@cummins.com
www.cumminspowersouth.com

[@Michael]

Originally Posted by @Michael

I have the same Crossfit/Onan setup. Non-diesel 15w-40 is hard to find. I ended up using Chevron Delos 15W-40 conventional oil. It's rated CJ-4/SM.

Originally Posted by booster

That oil appears to be double rated for gas and diesel, and the SM would indicate it is a reduced zinc additive package oil, so probably no better than a gas engine oil rated SM in regards to non rollerized engines.

Valvoline makes a 15w-40 SJ oil, but it's also diesel rated. Other than the OnaMax OEM oil I'm not finding SJ rated 15w-40 that is not also diesel rated.

AFAIK Redline doesn't have 15w-40 Powersports oil.

Next time I'll buy OnaMax and call it a day. I only run it an hour a month anyway - just to keep it from gumming up.

[booster]

Originally Posted by Deano

This is the email I received in response to my question about using synthetic oil in the Onan 2800 generator.

Good morning! I’m sorry it’s taken me as long as it has to respond, I have tried to be as thorough with your request as I can.
I have checked with technicians, service supervisors, and even one of our DFSE’s (Distributor Field Service Engineer) and they all recommend NOT using synthetic oil in this application.
This model does not have a pressurized lubrication system (no oil pump) and therefore also does not have an oil filter.
Synthetic oils are heavily reliant on oil filtration to remove dirt and other impurities.

I have attached a copy of the Oil Recommendations from the Owner’s Manual for this model, which I feel you already have a copy of, (this is all I can find for this application).

Please let me know if you have any questions or if I can be of further assistance!

Thanks, Kevin

Kevin Pierce
Parts Manager
Military Sales Specialist
Cummins Power South, LLC
1915 W. Oakridge Drive
Albany, GA 31707
(229) 888-6210 ext 6214
(229) 883-1670 fax
(229) 376-5712 cell
Kevin.d.pierce@cummins.com
www.cumminspowersouth.com

Not totally surprising, I think, that they would say that. My guess is that it really has little to do with the current contamination holding qualities of the dino or synthetic oils, as they all have to meet the rating standard for detergent effectiveness. It is more likely related to the possibility of leaks and oil burning if you take an older engine that has been run on old school oil and switch it to a modern, very high detergent oil. This was very, very common when synthetics first came out came out with lots of bad results as the engines cleaned out and go looser because the buildup was reduced. It is very possible that the original specs for that engine design called out non detergent oil, which was the norm for small engines with splash lubrication and no filters. The actually wanted the gunk to settle out to the bottom of the pan and knew it was unlikely that users would change an oil that held the contamination often enough to remove it. Not a lot of window of contamination in an engine that holds .5-1.0 quart and runs on a poorly designed carb and ignition setup. Any good new oil would probably do similar if the motor is sludged up.



All this said, IMO the Onan will not have any issue using Dino oil in 99% of the time of use. I think a top grade synthetic would only be of use if something bad happened that caused an overheat situation.