MEP-803A oil leak

My goof. I have a MEP-803A Fermont generator with about 1200 hours on it. Last week I noticed a significant oil leak that appears to be coming from the back, not the front of the engine block as I stated earlier.. It has an Onan engine. The oil leak stopped on its own for a while but is now leaking again. It is coming from the rear above the crank. I can't tell exactly where as it is mounted too close to the generator. Has anyone experienced this with these units? I need some good mechanic advice on how to troubleshoot this problem.

Welcome. Where are you seeing the oil? Is it being spun around the cabinet? Have you done any sort of troubleshooting to see WHERE its starting from?

A good troubleshooting aid is carb cleaner. You can clean off the oil and see where it's coming from.

+1 on the carb cleaner.

If you have not already done so, get the manual (it's on this site) and read up on leaks and maintenance.

I have no formal training, yet I've found these units are fairly easy to work with, especially with the help you can get here.

I have the same model and she leaks too, but it's minimal. At one time it did appear a lot of oil was leaking so I removed all the covers to get a better look. In my case the fuel lines had cracked enough to allow fuel to create the appearance of an oil leak. After running down the engine and accumulating oil residue along the way, it would pool around the battery boxes.

I cleaned it as best I could using cleaner, elbow grease, hot water, and brushes. I then replaced all the fuel lines. Left the covers off, topped off oil levels, and ran her a few days. She's been pretty good since.

I may be the first person to ever do this so I'm posting in case someone is considering it. Do NOT remove the oil cap while generator is running. Yes, hot oil comes spraying out.

Simple green or any other degreaser will work just as good with some water and not be so toxic.

Eather way you need to clean, dry and run while watching for the leak.

Like everyone said, clean it and start it, watch for leak. If it appears to be flinging oil onto the gen. doors etc. its probably the crank seal behind the crank pulley.
If so, its easy to fix. the seal goes into the front cover from the outside, just remove the lower pulley ( left hand thread on crank bolt if I recall? ) the pulley comes right off and seal is in the front cover. Use an Onan seal, the Chinese seals fit a little too loose into the cover, in my opinion. Or put some sealant on the OD if you have to use aftermarket seals.

Ray70 said:

Like everyone said, clean it and start it, watch for leak. If it appears to be flinging oil onto the gen. doors etc. its probably the crank seal behind the crank pulley.
If so, its easy to fix. the seal goes into the front cover from the outside, just remove the lower pulley ( left hand thread on crank bolt if I recall? ) the pulley comes right off and seal is in the front cover. Use an Onan seal, the Chinese seals fit a little too loose into the cover, in my opinion. Or put some sealant on the OD if you have to use aftermarket seals.

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Yes, left hand threads.

Better to buy the Onan seal, as then you know its right.

Like Bmxenbrett suggested, simple green. No fuss, no muss and you don't have to worry about your kids being born with three eyes because of chemicals.

Pull the top cover, I would also open, not pull the doors. That way, if you need to slap the top back on, to recreate the "Normal" air paths and currants to see where the leak is coming from, you don't have to fool with reattaching the doors. A nice trick we used, was to grind off the hinge pin heads, and drive out the hinge pins. Then we found a bolt, or quick release pin to fit the hole. When you want to remove the doors, its no big job. Simply pull the pis, and the door is off. Very handy for working on the sets.

Great tip on creating a quick release for the doors. I just put my doors back on and it slows the process down. If your unit is like mine and came with a solar panel on the top cover, consider a quick release connector (if not already installed) for wiring to the solar charger.

This post motivated me to recheck my unit and do a spring cleaning. I found a few acorns inside so I'll be doing some mouse proofing as well.

jrhunter said:

My goof. I have a MEP-803A Fermont generator with about 1200 hours on it. Last week I noticed a significant oil leak that appears to be coming from the back, not the front of the engine block as I stated earlier.. It has an Onan engine. The oil leak stopped on its own for a while but is now leaking again. It is coming from the rear above the crank. I can't tell exactly where as it is mounted too close to the generator. Has anyone experienced this with these units? I need some good mechanic advice on how to troubleshoot this problem.

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The oil leak is coming from the rear in the area above where the crankshaft is. It doesn't seem like a main bearing or seal leak as it is above those areas.

Oil or diesel ??

Motor oil

There isn't a heck of a lot above the crank that can leak oil. Just the rocker covers and head gasket.
Maybe try cleaning it good and get in there with a mirror and try to see the highest point where oil comes back.
Do you think it could be coming from the rocker covers and running down the back of the block?
Other than that you just have the oil pressure sensor and switch fed by a 1/4" ID hydraulic hose, make sure you don't have a pinhole spraying oil out onto the block. Basically, if its motor oil and you see it on the back of the block above the generator, it's probably a rocker cover.
Pulling off the top cover will give you a better view of the top of the motor.

thank you for the info. I'll begin pulling the cover as it is too tight in there to get a good view of the area. Thanks again.