Owner's Presentation - Cummins Onan Generator

[fagnaml]

I took my motorhome to the Cummins Coach Care Center in Houston this past Friday, 8/17/18, for generator repair (I have a separate post on that topic).   While there, the service advisor asked if I hadr seen the latest presentation Cummins has for owners of Onan generators from 2017.  Answer was "no" so he e-mailed the presentation to me which is attached for the forum to peruse.   

On slide 5 of the presentation, Cummins recommends against any modifications to the generator exhaust system including the use of Vertical Exhaust Extensions as such an extension cause additional backpressure on the generator engine (?).  During the football season, to assure a safe environment in the RV lots at LSU, the use of Vertical Exhaust Extension is required (I use the Camco extension shown on the green motorhome on slide 7).   There are hundreds of motorhomes at each LSU football weekend using vertical exhaust extensions!    The only option for an LSU football weekend is to NOT run the generator which would make all of our wonderful (tolerant?) football wives most upset !! 

What say you the forum that has a lot more Onan generator / small diesel engine knowledge than I ever will about using a vertical exhaust extension?  

Also, note on page 46 of the presentation that Cummins says NOT to use synthetic engine oil in diesel generators which does not make sense to me as synthetic engine oils are much more stable and have better additives than conventional motor oils.   Synthetic engine oils are designed to perform better / offer more protection compared to conventional engine oils.

In general, what does the forum think of this Cummins presentation for Onan generators?

Cummins_Onan_Generator_Seminar_Apr_2017.pdf

[wolfe10]

Thanks, Mike.  Pretty good presentation.

I agree, I would have re-phrased this after verifying with Cummins/Onan:

As presented:

Synthetic oil
– Okay on gasoline/LP Cummins Onan generators after initial break-in
– Not approved on diesel product
– Do not extend the published oil change intervals

 

Verify with Cummins/Onan, but perhaps:

Synthetic oil
– Okay on gasoline/LP Cummins Onan generators after initial break-in
– On diesel products only if the synthetic oil meets the API requirements (state the minimum API requirement-- perhaps CK-4 as of this date)
– Do not extend the published oil change intervals

 

[fagnaml]

Brett --

What are your thoughts on the use of the Vertical Exhaust Extension that Cummins says is a "no - no" ?

[ianbullock]

Hi Mike, thanks for sharing this presentation. Very informative. 

Basically my inclination is to follow to the manufacturer's recommendations to the letter. I have done so so far and after many years of use have not had an issue. 

[rossboyer]

With a stack or without a stack, people have died from carbon monoxide poisoning. But in general it is safer to not use the stack for the occupants, but may not be for your neighbor.

At one rally the generators running around us caused out CO detector to alarm at 7:00 pm with all the windows closed. We had to leave and come back at 11:00 pm when generators had the shut down. 

[dickandlois]

Mike, Brett covered things well. Regarding the synthetic oil. Back a month  or so ago - I questioned the backwards compatibility of T-4 compared to the T-3 and the consensuses was (if I remember correctly) was that the full synthetic  0-15 or the 5-15 blend was not meant for engines prior to the 2017 engines that need the new blends to meet EPA regulations. 

Regarding the use of the exhaust stacks - Coach builders often recommend them in there owners manuals. I have used one when ever we are parked in an area where one can run them 24 / 7. the exhaust will trip the Co detectors real fast if the exhaust is not vented upwards. Kind of thinking that Onan is covering a legal requirement, just in case the exhaust pipes have any leeks and there would be the possibility of a build up of Co.

Rich.    

[kaypsmith]

Pretty good presentation. CO is known as the silent killer, not Co2, CO dispels the oxygen within it confines, which first brings on sleepiness because of the low oxygen content, this puts the unlucky recipient to death without realizing what is happening, therefore I liked the fact they are making all aware of the need for CO detectors and the reason for no stacks attached to the exhaust pipes. I never gave much thought to the no synthetic oil, but I never had a reason that made me want to use it. An added thought, CO is commonly called carbon monoxide, as stated earlier, very deadly.

[fagnaml]

Regarding the question of using synthetic oils in Onan generators, since my company (Phillips 66) owns Redline Oils (manufacturer of high performance synthetic engine oils), I contacted the tech services manager I know at Redline especially since I'm using the Redline synthetic 15W-40 engine oil in my generator.   The Redline tech services manager was not aware of Cummins saying "no" to synthetic oil in Onan generators so he contacted his counterpart at Cummins.   The Cummins technical manager said the reason for saying "no" to synthetic oils for generators is to help assure that owners do no go beyond the 150 hour max run time between oil / oil filter changes.

Reason is, the small Kubota three cylinder diesel engines have a "fair amount" of exhaust gases / exhaust particulates leakage into the engine oil which greatly impacts engine oil performance.  Cummins acknowledged that synthetic oils are more robust in handling exhaust gases and are more thermally stable, the small oil filters on Kubota engines can only handle certain amount of particulates before oil flow is adversely affected.    For the reason of oil filter "particulates loading", Cummins does want owners to think that by using a synthetic oil that the max 150 hours run time between oil changes can be extended.

Bottom line, the answer is synthetic oils can be used in Onan generators on the basis that run time between oil changes is not extended.

For me, using a synthetic 15W-40 engine oil in my generator gives me an additional level of comfort that my generator, running 24/7 for 48 hours on a hot, humid September weekend in Baton Rouge will have the lubrication protection it needs.