Onan Drip Pan Replacement

Drain the oil, unbolt it and roll it over on its side, replace the pan.
The pan is simple.

The difficulty and labor cost will be area you have to work in.
You may have to pull the whole gen-set out of the boat.
If you go that far, consider re-installing a new set.

I think there may be a terminology misunderstanding here. I think the OP is referring to the "drip pan" under the entire gen-set frame, and the responder is referring the the engines "oil pan".

Ah, I understand your comment. I was not in tune with the OP.
Drip pan replacement will also be labor intensive and subject to room available.
You would be amazed, OhNo may still stock a new pan / tray. If not a good meal shop can repair or build a new one.
Sound shields and covers off,
Bonding straps from the block to the tray off,
Any strain reliefs off,
Tray un-bolted from the deck,
Motor mounts un-bolted,
Jack up or from overhead, raise the engine,
Slide out old tray/ Slide in new tray.
Reassemble in reverse order.

With no idea what boat it's in,
No gen-set model number,
No pictures of gen-set,
As anybody else can type the same generic R&R plan as I did,
Nobody can offer real $$s.

Agree, it's too difficult to estimate cost without boat/pictures etc. But It's a pain in the ass of a job even with good access. Sometimes you can get away with jacking it up with bottle jacks and blocking it to get the pan out from underneath, but overhead lifting is usually the preferred route.

Is there a reason the OP couldn't just slide a slightly smaller pan inside the old or even just float resin into the pan to seal it?

Or a come along or ratchet winch supported overhead from structure, either permanent structure or temp. Have a fab shop build a stainless pan, and upgrade the engine mounds upon reinstall.

The thing should only weigh like 400 lbs or so.Why not just make a simple lifting jig out of some wood 4x4’s or similar? Lift it up, remove and replace. If you don’t have enough clearance above, slide some steel angle iron pieces under the block and use a porta-power with some pancake jack heads. Really shouldn’t be that hard. If you don’t feel comfortable undertaking this should be a routine project for just about any service provider.

I wondered about this last night.
Is this the early Cummins-OhNo's?
Cummins MD3 bolted to an old alternator end?
There was so much heavy sheet metal around them to sink a dink.
Removing all that sheet metal will be a job.
There are not many spare parts left for these motors and hard to imaging any trays left.
Making a new pan and attaching all that sheet metal back on will be also a challenge.

What is your tray failure?
Repairable in place?
You find any model numbers yet?

The Cummins/OhNo web site has changed. No more free manuals.
I did find this PDF in my archives.

Later Kubota with OhNo original styled round alternator.
around 2004 model.
These trays may still be available.
Still lots of sheet metal attaching to the tray.

Pull yours and have them blasted and repaired would be my first idea to offer.

Heavy rascal. Starts @ 640lbs.

How many hours on yours? You may consider shopping for new sets.
Close to R&R expenses either way.

You don't want to underload gens. So when things like air conditioning aren't used the smaller gen would be the one to use.

Well, I'm still thinking.
It's a labor intensive job that will be hard to quote before hand by anybody.
Is it a glass or wood deck under the tray?

Tell me about your ospho try.
All real clean before it's application?
Real metal primer used soon after?
Real quality paint over the metal primer?
Final paint left to dry several days before it got wet?
Is there sitting water often in the tray?

How is the tray under the 21.5?
Hours on the 21.5?

Or, do you want a matching 21.5?

If it's an older generator, I would just put a new generator.....Either ONAN or Northern Lights and be done with it, before I go through all that.

It seems to me that having a larger and a smaller gen was popular a while back. Some called that a night gen. All the boats built since the 90s that I ve run Seem to have equal sized gens.

The newer gens with computer controlling can handle the lighter loads with no issues. Every yacht I've run that had a smaller gen, it NEVER got used, because it was never useful. Always tripping the breaker when someone turned the microwave on or a burner or two, resulting in starting the bigger gen and switching over, rather than slowing down or taking a trip down to the engine room to reset the breaker. Perhaps in the PNW it might be useful. But generally you have enough loads on the newer yachts with stuff like zero speed stabilizers at night as well as HVAC, water heater......water maker, etc. Plus having 2 equal gens means being able to carry more useful spare parts.

Some boats can work with a smaller gen-set at night, some can not.
We have a 30kw, 9kw gen-sets and auto 4kw inverter.
Did not like running the big set un-loaded. We put the 9KW in.
Always had some inverter available.
No need for a gen-set when the weather is pleasant on our trips.

Sorry to get off topic. I did open up the distraction in my last line in post #15.

I really like my set up with a 20k and 9k . The 9k covers my needs 90+ % of the time. I only need the 20k when if using the dryer, watermaker or lots of stuff at once. But, of course, I’m not using A/C.