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Topic: Onan 7.5 Genset Oil (Read 1301 times) previous topic - next topic

Onan 7.5 Genset Oil

Am preparing to change generator unit oil tomorrow, and wanted to get the consensus here on petro- vs. synthetic. My genset has 1,100 hours, in all likelihood all on Delo 400. I've used the Delo 400 for many years in my diesels, but have run Schaeffer 9000 full synthetic in my Mercedes diesels some years now, experiencing improved lubricity and lower wear. Would it be a good idea to use synthetic in my genset or should I stick with the tried-and-true Delo 400?

Thanks!
1989 Foretravel U300 Grand Villa
Build #3410

Re: Onan 7.5 Genset Oil

Reply #1 –
I run synthetic in mine, but I do 500+ hr changes. With such little usage I doubt you would see any benefits of the synthetic over a good conventional.

That said, Schaeffers 9000 is one of the finest oils available anywhere and will be an excellent choice.
95 U300SE

Re: Onan 7.5 Genset Oil

Reply #2 –
I believe any air cooled engine would benefit from a switch to synthetic. The 12000 rpm + high horsepower motorcycle guys seem to prefer the rotella synthetic.
Let the games begin. Price point is narrowing, and the typical low hours on a genset may not suggest the change. Then again if they genset engine fails, I would guess you replace the entire unit at $$$$. Just my 2 cents.
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake

Re: Onan 7.5 Genset Oil

Reply #3 –
Sorry Randall, I pulled out my 89 foretravel manual and low and behold. A 7.5 kw water cooled diesel  onan 7.5 DKD appears as an option in 89 and oil change intervals based on foretravel recommendations at 75 hours. 10w30cd.
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake

Re: Onan 7.5 Genset Oil

Reply #4 –
Fred, would this, in your opinion preclude the switch to synthetic? And 10w30 instead of 15-40 if dino?
1989 Foretravel U300 Grand Villa
Build #3410

Re: Onan 7.5 Genset Oil

Reply #5 –
Here's a thought,what if Barndogs engine was running synthetic and he shut it off in time and did not have any damage?Had a friend
back in 1978 driving a BMW 2002 to CA from Chicago,his oil drain plug came loose and he lost all the Amsoil,no damage to the
engine and he still has the car.Did the synthetic oil help,it surely did not hurt.
96 U270 BUILD 4810
85 380SL
Drummonds TN.

Re: Onan 7.5 Genset Oil

Reply #6 –
Randall diesel RV gensets of that era maybe hard to find or even economicly repair, I sometimes wish I had one. A call to onan may get some recommendations on oil. But I run synthetic rotella thru my  83 mbz 300SD forever car for about the last 10 years. speedometer broke at at 250 k. I think I've got about 400k on it now.
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake

Re: Onan 7.5 Genset Oil

Reply #7 –
I am using Rotella 15w40 with 1 at Lucas Oil Treatment.
91 GV U300 Unihome 40' Build 3811
6V92TA Detroit

Re: Onan 7.5 Genset Oil

Reply #8 –
Yep, I run strait synthetic in my diesel Benzes and have never had a problem, over 400K on the 300SD.
1989 Foretravel U300 Grand Villa
Build #3410

Re: Onan 7.5 Genset Oil

Reply #9 –
Randall there are some onan pdf manuals floating around on the web for the 7.5 DKD that show 100 hr oil changes intervals vs the ridiculous 75 hr intereval in the foretravel info. which would may limit the amount of boondocking without changing oil. Check with onan with synthetic you may be able to extend the intereval.
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake

Re: Onan 7.5 Genset Oil

Reply #10 –
Most of us just use the same oil in both main engine and generator.  KISS.
Regards,
Brett

'99 42' Foretravel Xtreme
'14 Brown Motorsports Stacker
'05 Chevy SSR
'02 BMW R1150R

Re: Onan 7.5 Genset Oil

Reply #11 –
Quote from: RvTrvlr –
I run synthetic in mine, but I do 500+ hr changes. With such little usage I doubt you would see any benefits of the synthetic over a good conventional.

That said, Schaeffers 9000 is one of the finest oils available anywhere and will be an excellent choice.
Dino is Fino yearly..IMO
Hans & Marjet
1995 U300 "Ben" (#4719)
3176B Cat,4060HD,Jake
SKP#139131
Motorcade#17579
2006 Honda Element (towed)

Re: Onan 7.5 Genset Oil

Reply #12 –
Quote from: amos.harrison –
Most of us just use the same oil in both main engine and generator.  KISS.
Amos Those of us with Detroit 6V92  2 strokes cannot do that we have to run straight 40 wt low ash oil in these engines.
91 GV U300 Unihome 40' Build 3811
6V92TA Detroit

Re: Onan 7.5 Genset Oil

Reply #14 –
Well I wouldn't run the same in both, because I use 40W in the Detroit, and would prefer a multi-grade diesel oil in rhe generator. My dilemma is between 15w-40 petroleum oil, or (my preference) Schaeffer 9000, a full 15-40 synthetic.
1989 Foretravel U300 Grand Villa
Build #3410

Re: Onan 7.5 Genset Oil

Reply #15 –
I run full synthetic Amsoil 15W-40 in both my engine and generator.  Been using this for over 10 years now full time in this coach.  I am comfortable with the added protection and benefits from full synthetic oil.  It sounds like you have had good success with synthetic oil in your diesel Mercedes- it is a personal choice. 

In the words of our late friend Dave M-  do what makes you happy.

Cya down the road............. ^.^d
Ted & Karen
2001 U270 36' - sold after 12 years full timing