Onan 7500 oil loss

lenp · December 12, 2022

Stopped in a parking lot for a break and a cup of coffee Friday. Started the generator and it ran for a minute or two and quit - started it again and it quit in a few seconds.... Went out to check it and discovered a pool of oil under the unit and NONE on the dip stick. DARN!!!

Crawled under it today and dropped the filter inspection cover and all looked dry but the entire bottom of the unit is saturated in oil. It will still start and run (but I only let it run a couple seconds due to no oil - I wanted to make sure it hadn't thrown a rod or something). I am assuming there is an oil line or breather tube on the side of the block that has come loose but it looks like the entire unit needs to be removed before the side panels can be removed. That will have to wait until I get home around Xmas time.

Any thoughts on what I should look for?

Thanks for any thoughts/suggestions.

Lenp

Wrknrvr · December 12, 2022

The first thing to think about would be to borrow or buy a remote camera. Harbor freight has them.

Then you could search around with that. That may tell you where the leak is. And what it is.

If the generator is not on a slide, you may need to get it out so you can fiscally get the panels off and look. But hopefully the camera will tell you where to look.

Also you need to keep a good attitude about such subject.

lenp · December 12, 2022

Thanks for the input. Have a camera at home and will try that first. It is on a slide but even when slid out the side panels appear to be blocked by the slide frame. Looking at the service manual there is crankcase breather tube running up the side of the block - wouldn't surprise me if it broke or came loose.

Bought a Honda 3200i to get us home. Hopefully won't even have to use it but just in case we get stuck somewhere in the weather between Arkansas and Oregon we are prepared.

Lenp

Wrknrvr · December 13, 2022

You could get stuck in the weather in those travels

Ray,IN · December 13, 2022

Lenp, look at the top cover, if I remember correctly it may be removed without removing the rest of the enclosure. I think the oil opening to add oil, has a rubber tube to the motor

lenp · December 14, 2022

Ray, I will have a look when I get home. I don't want to mess with it in a RV park. Just my luck i would think I had it fixed and put more oil in and have it all over the ground again.

Might not get to it right away with the cold weather in Central Oregon but will advise if/when I figure it out.

Thanks for the input!

Lenp

lenp · December 27, 2022

We made it home on the 20th (two days before the DEEP freeze hit Central Oregon). Hustled to get the MH unloaded and winterized the next day.

Today temp was in the 50s so decided to take a look. Took the top cover off but couldn't see anything obvious. Took left (drivers) side off and again, nothing obvious. Added a few quarts of oil and fired it up. Once again oil coming out but this time (with covers off) easy to see it was coming from the filter!

I had checked that the filter was tight when we were in Arkansas and it was. I got my BIG channel locks and gave it another half turn. Fired it up again and now even more oil coming out than before.

Replaced the filter and all is good! I suspect the filter was probably overtightened when I had it serviced resulting in the gasket being squished too far. Amazing it lasted several months before leaking. A close look the the gasket shows no sign of a failure or anything. That Onan oil pump was really pushing the oil out - must be a good pump!

Could have easily fixed it on the road but did not want to chance an oil spill in a campground. Glad I waited though due to a large amount of oil got into the space the generator pan and the slide out pan it sits in. At least here I could wash it out without fear of a campground owner getting PO'd.

Thanks for all the suggestions! Much appreciated!

Lenp