Originally Posted by Aussieflyer
Within two hours operation on ashless dispersant oil I started getting a puddle of oil on the floor after every flight. Examination revealed the oil was dripping out of the sniffle valve (intake manifold one way valve).
It is actually fuel residue.
It is unlikely what you are seeing is oil (though I admit it certainly looks like it). Check it with a white towel/Kleenex and you will likely find that it has a definit dark blue color from highly concentrated fuel dye.
There is no path for oil between the main engine sump and the induction manifold other than the intake valve guides, so accumulation of oil that would drain from the sniffle valve would have to come though the intake valve guides and then migrate down the induction tubes, or have a pathway that shouldn't exist because of a faulty engine casting.
A simple test to prove it, is to run the engine at about 1200 RPM for a minute after a flight and then shut the engine down by positioning the fuel selector to OFF and let the engine quit. This will bleed down all system pressure before shut down instead of it bleeding down into the induction system afterward.
This has been some what common on 390's vs some of the other models for reasons that no one has been able to explain to me.
Point is, it probably has nothing to do with your break in or change of oil type......