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Topic: Onan 6.5 Emerald Plus 6500 Gen Set Oil Leak (Read 620 times) previous topic - next topic

Onan 6.5 Emerald Plus 6500 Gen Set Oil Leak

I'm finally getting around to putting the door back on my generator compartment after replacing the generator's starter and figured I would find and fix the oil leak before I do.
Here are some photos showing where the oil ends up. I'm going to thoroughly degrease it to verify where the leak is. Does anyone have an idea of where it might be coming from? Know of a good degreaser?
1993 U225 Build #: 4285
500 Watts Solar
Honda CRV AWD
Former 1981 Foretravel Travco
Retired, Full Time Off Grid Snowbird

Re: Onan 6.5 Emerald Plus 6500 Gen Set Oil Leak

Reply #1 –
Wonder if at some time the oil was over-filled???

I would clean it up (roll of paper towels and some WD-40 and re-evaluate.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Onan 6.5 Emerald Plus 6500 Gen Set Oil Leak

Reply #2 –
It could also be the low oil pressure switch which is fairly close to the oil filter.
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins

Re: Onan 6.5 Emerald Plus 6500 Gen Set Oil Leak

Reply #3 –
Quote from: wolfe10 –
Wonder if at some time the oil was over-filled???

I would clean it up (roll of paper towels and some WD-40 and re-evaluate.
Thanks Brett. I did as you suggested and cleaned it up pretty well using WD40 and a roll of shop towels. I don't use the generator very much and I believe this leak started when I replaced the starter about 2 years ago. I changed the oil & filters then and today the oil level was 1/2 quart low. Other than exercising it, I ran it for about 12 hours last summer when the power went out.
I searched this forum and found nothing about oil leaks on this model Onan but I did find some info elsewhere on the web. Suspect leak areas are:
The oil drain pipe/valve -- either loose or needs pipe dope;
**The exhaust bracket bolts -- remove and replace adding some gasket sealer.
(I had to remove the exhaust to get the generator out far enough to replace the starter.)
I brought the oil level up to the add line. I'll do a little more cleaning and then use the baby powder trick to see if I can pinpoint the leak.   
1993 U225 Build #: 4285
500 Watts Solar
Honda CRV AWD
Former 1981 Foretravel Travco
Retired, Full Time Off Grid Snowbird

Re: Onan 6.5 Emerald Plus 6500 Gen Set Oil Leak

Reply #4 –
Quote from: red tractor –
It could also be the low oil pressure switch which is fairly close to the oil filter.
Thank RT. I'll check that as well.
1993 U225 Build #: 4285
500 Watts Solar
Honda CRV AWD
Former 1981 Foretravel Travco
Retired, Full Time Off Grid Snowbird

Re: Onan 6.5 Emerald Plus 6500 Gen Set Oil Leak

Reply #5 –
Best way to get it spotless would be a air hose siphon sprayer and a gallon of mineral spirits,do not get water any where near the generator.
96 U270 BUILD 4810
85 380SL
Drummonds TN.

Re: Onan 6.5 Emerald Plus 6500 Gen Set Oil Leak

Reply #6 –
Okay so the oil leak is a minor leak. Since this started during your last oil change and it was a couple years ago, this would be a great time to change the oil again. Placing dry paper towels in the area will rat out an oil leak. Take a close look at the filter you remove and see if there is any evidence of the prior leak. Silicone grease on the gasket when installing 3/4 of a turn tighter after the gasket makes contact. Oil pressure switch could also be your culprit as mentioned. I feel your ONAN pain

Re: Onan 6.5 Emerald Plus 6500 Gen Set Oil Leak

Reply #7 –
Quote from: dsd –
Okay so the oil leak is a minor leak. Since this started during your last oil change and it was a couple years ago, this would be a great time to change the oil again. Placing dry paper towels in the area will rat out an oil leak. Take a close look at the filter you remove and see if there is any evidence of the prior leak. Silicone grease on the gasket when installing 3/4 of a turn tighter after the gasket makes contact. Oil pressure switch could also be your culprit as mentioned. I feel your ONAN pain

Pictures are of totally different generator.  But the advice is GOOD.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Onan 6.5 Emerald Plus 6500 Gen Set Oil Leak

Reply #8 –
Quote from: dsd –
I feel your ONAN pain
Ouch. I feel your pain Scott.
You are correct, mine is a minor leak but it is a bit messy and it would be a lot more painful if I put the compartment door back on (48 screws if I counted correctly) and had to turn around and take it off again to fix the leak. I have new oil and filters on hand. Just dusted the likely leak spots with baby powder and ran the generator for 20 minutes. No signs of a leak yet. I'll check it again in the morning.
1993 U225 Build #: 4285
500 Watts Solar
Honda CRV AWD
Former 1981 Foretravel Travco
Retired, Full Time Off Grid Snowbird

Re: Onan 6.5 Emerald Plus 6500 Gen Set Oil Leak

Reply #9 –
I am surprised you need to remove the door vs just releasing the air shock/piston to get enough clearance to pull the generator out.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Onan 6.5 Emerald Plus 6500 Gen Set Oil Leak

Reply #10 –
Quote from: wolfe10 –
I am surprised you need to remove the door vs just releasing the air shock/piston to get enough clearance to pull the generator out.
I wish that was the case. The door jamb (right, to the rear) and bottom seal/trim piece prevented the generator from sliding out. There is a little room on the left (front) side. If I had the right kind of lift and some help I may have been able to jockey it out.
I could be wrong but I think Foretravel put the generator in before they put on the door and trim. 
1993 U225 Build #: 4285
500 Watts Solar
Honda CRV AWD
Former 1981 Foretravel Travco
Retired, Full Time Off Grid Snowbird

Re: Onan 6.5 Emerald Plus 6500 Gen Set Oil Leak

Reply #11 –
My onan project will be off the forklift in the morning, you're welcome to stop by and use it if you end up pulling it out
Scott

Re: Onan 6.5 Emerald Plus 6500 Gen Set Oil Leak

Reply #12 –
Wonder if you can unscrew the propane regulator and that will allow the generator to come out?
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Onan 6.5 Emerald Plus 6500 Gen Set Oil Leak

Reply #13 –
IIRC our 240 you had to get a floor jack under the generator frame. Once you had a load on the jack there were 2 or 3 bolts that you removed and could let the generator tilt down.  This would give access although not much to service the backside of the generator.

Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Onan 6.5 Emerald Plus 6500 Gen Set Oil Leak

Reply #14 –
Quote from: wolfe10 –
Wonder if you can unscrew the propane regulator and that will allow the generator to come out?
I actually did unscrew the regulator at one point but if you look at the photo, the frame it is secured to extends as far. That photo is with the door and the rh trim already removed.
There is also a bay height issue in this (and I presume other) U225's. As I said, Foretravel must have installed the generator with a shoe horn before adding the door trim, the door and several other things including the hour counter.
As for the leaking oil, it appears to be from the exhaust bolts.
1993 U225 Build #: 4285
500 Watts Solar
Honda CRV AWD
Former 1981 Foretravel Travco
Retired, Full Time Off Grid Snowbird

Re: Onan 6.5 Emerald Plus 6500 Gen Set Oil Leak

Reply #15 –
So im not real familiar with Onans and one of my life goals is to never work on another one. EVER! Ive never seen an exhaust stud that was in an oil wetted part of the head. Would suspect the oil leak is above it from possibly the valve cover? Just guessing. I got my Onan belt project off the forklift and all hooked up but the SOB coach while the battery were switched off decided to not cooperate by powering down the battery buss for the generator . So it's in and I'll look tomorrow to try and troubleshoot that so I can see if the generator is problem is resolved. Same buss also powers the Hydraulic leveling system and the pump wont operate.

No good deed goes unpunished
Scott
3-15 update, found the owners manual. Cursed searching threw it. Found a horrible wiring diagram and located tripped relay, reset and everything resolve. This SOB doesnt stand for Brand.

 I appreciate the old Foretravel even more today.
 

Re: Onan 6.5 Emerald Plus 6500 Gen Set Oil Leak

Reply #16 –
Got the door back on. Here is a photo of it plus another showing how the right side and lower door trim pieces prevent this generator from coming out. It's not that hard to remove them.
 
1993 U225 Build #: 4285
500 Watts Solar
Honda CRV AWD
Former 1981 Foretravel Travco
Retired, Full Time Off Grid Snowbird