Oil Leak At Sump Gasket, IO-540
 

I have developed a leak at the sump gasket at the rear right corner where the sump gasket and vertical gaskets meet. After cleaning I used foot powder to find the source of the leak. After running the engine for 5 minutes it was very noticeable. Left alone the oil will run around the perimeter of the sump seam and gasket and get blown everywhere. The engine was rebuilt and has 65 hours on it.

What is the best approach to fix. Any of the following or a combination work well? Self Wicking Locktite 290, Permatex Spray Sealant Leak Repair, Permatex The Right Stuff, Proseal.

Has anyone had success fixing a like like this? Hopefully this can be fixed or at least slowed down. I can live with some small leak but the way it is now is unacceptable.

Thanks in advance for any help or suggestions.

I'd give the area good degreasing ( break cleaner works great) then a scrubbing with a toothbrush size wire brush & rinse off with break clean and try the wicking Locktight ,give it overnight at least to set. If that doesn't slow it down or stop it clean up again and smear on the Proseal. ( remember Proseal takes quite a while to cure)

Its no fun, but its pretty easy to replace. I'd try the above comment first.

You need some type of sealant where sump gasket crosses the accy case gasket. your builder may have missed this. I don't think a wicking sealant will do it. There is no real way to get the oil out inside the joint, where you want it to wick into. Until you are ready to pull the sump, I would agressively clean the outside and use an external sealant, such as proseal or RTV (this is temp only, as it doesn't hold up long term in this application).

Larry

Have you tried re-torqueing all of the sump bolts? I would try that first. If that does not do it, it is not hard to drop the sump down an inch and fix this correctly with a new gasket. The biggest issue is that you need to get the surfaces dry and the oil seems to drip down from up above for ever. After dropping the sump (leave it right inside the area captured by the exhaust) let the oil drip for a day and then clean it up really well before inserting the new gasket.
I would then add a dab of gasket sealant at the corner where the two gaskets meet. The likelihood of sealing it from the outside is almost nil, and in the same amount of time you could fix it correctly. It is an airplane after all :)

I did re-torque all of the bolts and nuts without any success. I didn't want to over torque them but they are all now vert tight. When I get to the hanger tonight I will look at what is involved in dropping the sump to replace the gasket. But if memory is correct, the engine mount is also in the way in addition to the exhausts. If I do drop the sump and have little clearance will that make it difficult to get the new gasket seated correctly?

In the meantime if I did use proseal on outside to help seal it, will that create more issues removing it, cleaning and then dropping the sump later?

I would completely pull it, if you can. It is much harder to get the surfaces clean if the gasket stuck. Being relatively new, it may pull right off. You'll also want to wipe the oil off the inside walls a bit to keep it from dripping on the new gasket. It doesn't take but a few minutes to pull the exhaust and Vetterman includes reusable gaskets. Just maintain the placement and orientation. I haven't hung the engine on my 10 yet, but you only need to drop the pan about 1" then you can pull it forward quite a ways if you need to clear the mount.

A temp pro seal fix will create a bit of work to clean up later, but nothing insurmountable. Just make sure the location will allow you to get a razor blade in there to slice it for removal. You don't want to be beating on it for removal. If you do this, it is critical that the gasket reveal that you are covering has had the soaked oil removed. If not, the pro seal won't adhere to that bit of gasket and the oil will follow that path and leak again.

Larry

Keep in mind removing sump on 0-540 you will need to have some way of raising and supporting engine due to mount ears on the sump