OIl leak

[Guenter]

Hello Sailors, I am new to the forum and hope this is the right place to post my question to fellow C34 MK1 owners:

My Universal engine has developed an oil leak, dripping right under the oil pan, to the left hand side. I have read a lot about leaking oil pan gaskets and this could well be my problem as well. Since the boat is out of the water (Lake Michigan, January 2024), I can't run the engine right now and exame where the oil is exactly coming from. But, I believe it is either coming from the oil pan gasket or (hopefully not) from the rear oil ring inside the bell housing. But my thinking is, since the lower edge of the bell housing is below the oil pan gasket, it is unlikely that oil from the bell housing drain slot would spray up to the oil pan gasket, but certainly the other way around, as gravity would do its thing.   
- The boat is a 1986 Catalina 34, the engine is the original Universal 25HP engine.
- The engine is relatively clean in the upper section, so head gasket and valve cover gasket can be pretty much ruled out.
- Also, once a certain amount of oil has leaked, the leak seems to stop (because of lower oil pressure, I assume). I know that because the leak was already there all through the 2023 season. The loss of oil is within the dipsticks upper and lower level.   


So, my question to the forum is:

- Has anybody experienced an oil leak on the rear oil ring in the bell housing? My front oil ring seems to be doing OK.

The engine is going on 38 years, @3,000hours this may be possible but I am hoping it is the oil pan.

Any advise, sharing of your experience would be appreciated.
Thanks,
Guenter, Seaclypse , 1986 C34

[Ron Hill]

Guenter : I assume that the "left side" of the engine is the starboard side??

A thought

[KWKloeber]

Guenter

I doubt that it is from the pan gasket.  The oil level in te sump is below that and there's no pressure to push oil past the gasket.  I'd think that it would need to be a seriously obvious compromise of the gasket to do that.

Had you laid down a pad to tell exactly where it is dripping from?  Leaking Oil can travel and drip in another location!

Help us help us you!  There are no left and right on a boat! 
Maybe a photo showing where you think it's dripping from?  Or a very good description.

-Ken

[Paulus]

Yes, but it was coming from the valve cover casket at the rear of the cover.  (after spending a few boat $$)  Hard to see but worth taking a good look at it.
Paul

[Jim Hardesty]

Guenter,
My suggestion is to clean the engine very well.  IMHO something that should be done anyway.  Then if the leak still isn't apparent. Use some oil dye and UV light.  If you buy at a auto store they may loan the light.  Here is what I'm talking about.

www.amazon.com/Interdynamics-Certified-Fuel-Systems-Ounce/dp/B002M4G24U/ref=asc_df_B002M4G24U&mcid=1aa8ea0212b63905a3180df946dffadb?tag=bingshoppinga-20&linkCode=df0&hvadid=80195684681657&hvnetw=o&hvqmt=e&hvbmt=be&hvdev=c&hvlocint=&hvlocphy=&hvtargid=pla-4583795260966411&psc=1J

Jim

[Ted Pounds]

If you have a water source you can run the engine.... Just make sure you winterize it again when you're done. 😉

[Stu Jackson]

If you have a water source you can run the engine.... Just make sure you winterize it again when you're done. 😉

Here's how:

Winterizing an Engine on the Hard (Thanks to Maine Sail) - NEVER connect a hose to your raw water pump inlet - NEVER!!!

https://youtu.be/PKky09u1fGU

Just don't put the engine into fwd or rev when on the hard or you'll kill your cutlass bearing.

[Ron Hill]

Guenter : If you can't find the oil leak by putting a "fuel diaper" under the engine (after you clean the sides and bottom) then go with Jim's oil dye idea!!

a few thoughts

[Guenter]

Sorry for not getting back here earlier to all your inputs (I was travelling)- Thanks for that.

No, leak is port side under the oil pan

- valve cover gasket rear end is certainly possible - Thanks Paul
- and yes, a good deep clean of the engine is in order as well, you are right on about that, Jim 
- water source available as soon Marina turns the main valve back on, likely end of March, I may consider running a water hose into a bucket and let the cooling water intake hose suck from the bucket - all in neutral, of course.

I will report back what I find. If it is the valve cover gasket, it should become apparent as strong as the leak appears to be with a full oil pan. A possible path is down the aft side if the valve cover onto bell housing, oil pan and into the engine bed and from there into the bilge)   

[Ron Hill]

Guenter : The valve cover "gasket" is actually a long "O" ring. It sets in a grove in the valve cover itself. You should be able to easily get a new one at a Kubota Dealer. 

Just pray that it is NOT the rear crank shaft seal inside the bell housing.   

A thought

[Guenter]

Ron -

yes, I am hoping that too. Getting at the crankshaft oil ring is no small task. But I am prepared to do that as well, if need to. From what I have gathered from the service and part manuals, the oil ring sits in a plate inside the bell housing that is bolted to the engine block. But getting at it is difficult - moving the engine into the galley is probably in order for that. I also contemplated to cut into the air louvers underneath the companionway and the "box or shelf in the aft cabin to have better access to the engine, otherwise it will be boat yoga. If done right, it could be removable for future access to the engine, but I am not sure about structural integrity.

I am sure other owners had thoughts of that as well. Any experience with that?

Thanks for the advice,
Guenter

[Ron Hill]

Guenter : I went thru that with my original M25XP engine !!!  If that rear lipseal is leaking you might also want to change the race that the lipseal rides on.  I removed the engine from the boat as it's NOT a simple task to change out that lipseal and the race!!

A few thoughts

[Guenter]

Ron - thanks for the input. So, this lip seal does seem to fail with the original Universal engine as you are confirming. So, my questions to you would be:

1) May I ask how and where you detected the leak? Did you detect an oil puddle portside under the engine block and oil well in the engine bed (off-center between the engine mounts on the compartment floor with drain hole to the bilge?) Did your leak improve ( less oil loss at less oil in the pan and at lower pressure ? ) 
2) Getting at the lip seal would involve removing transmission, bell housing, flywheel and the plate the lip seal sits in ( is that what you call the "race" ?) - replace, reassemble, re-install engine into place, correct?  Do you think having the engine out of the engine well, propped up in the galley would be an option? Pulling engine off the boat would mean for me while boat is in the water - I'd prefer to do it when boat is in the yard, but means engine stays in the galley
Thanks in advance,
Guenter

[Ron Hill]

Guenter : Look in the old Mainsheet tech notes and I have an article on replacing that rear crank lipseal.

Mine leak was soo bad that I couldn't keep oil in the engine!!  Just hope that isn't the problem!!

A thought

[ewengstrom]

Guenther,
I'm addressing nothing but engine removal in this reply just in case you decide that is the path you need to take.
I pulled the engine on our boat for heavy maintenance and oil pan gasket replacement. I simply made a stand out of wood the same height as the engine bed, removed the dipstick tube (that was the hardest part) and slid the engine onto the stand. It lived in the galley for a few weeks while all the work was completed and then I rigged up a lift in the companionway hatch to help ease it back into place. I reinstalled the dipstick tube after the motor was reinstalled....again...that part wasn't fun.
Everything was done by me, alone...and it wasn't too difficult to accomplish.
Oh, and the boat was in the water during this project too.
Hope these pics help if you go this route.