Quoted From skim3544:
If you are positive that it is not coming from the top, then this could be due spark plug tubes leaking the oil into the hole through the bottom side. The bottom is usually mounted to the cylinder head with a gasket or RTV.
http://www.realfixesrealfast.com/realfi … tubes.html
That IS true but it’s rare, I’m of the philosophy to go for the easiest solution first as getting those tubes out to reseal them can be a real challenge.