Peter wrote:
How can you have a leak there on a stationary engine, when the oil should be way down in the sump?
That’s, even in wording, exactly the question I asked myself ^^
Clearly, it is impossible.
But if oil really keeps coming out after the engine has stopped, it could be you have a crack in the crankshaft end / the propeller mounting flange, and the fair quantity of oil which sits inside the crankshaft (this oil is normally used to pressurise the prop governor) could be leaking out for quite a while.
I wouldn’t want to run the engine like that, let alone fly with it.
Hmm… yes, I can imagine that, as far as the prop mounting flange is considered. It would have to be either before or directly underneath the seal. That is possible.
But if it is in the inside part of the crankshaft behind the seal (the black part of your picture) – it wouldn’t leak through the seal, would it ?
My view, worth what you are paying for it, and given that we have no engine builders posting here (they tend to shy away from social media at any cost 
) is that if you have lots of oil p1ssing out with the engine stationary, the leak has to be outside the front of the oil seal.
On the plus side, for oil to be leaking from a crack, you would see the crack. Clean it up with avgas and watch.
Probably not easy with the prop screwed on, because you can’t get in there veru well. A narrow borescope may help.
Could it be leaking from the prop-crank interface? There is an o-ring seal there, IIRC
I have an oil drip from the O200 in the hangar. Suspected at vacuum pump, I’m getting it fixed by an engineer next week. Not noticeable oil loss, but noticeable on floor if the pan is not in the right position.
Oil leaks when engine running. Sticks on engine etc. Then drips off slowly over days. Probably microlitres, but it stains the floor.
I’ll have it checked tomorrow and will see ! Thanks for the hint
