Oil leak aft section

Christian, I recently arrived at my hangar, only to find a huge puddle of oil under my airplane.  As usual with oil spills, it looked like a gallon on the floor, but was probably less than a cup total...  

I pulled off the cowl and checked the engine for leaks by wiping it down everywhere I could reach.  The only oil residue I found was on the side of the oil tank itself, and on the cowling directly below the tank.  I got a local A&P to come look at it with me, just to be sure.  We could not find any leaks.  We ran it up (sans cowl) and there were no more leaks.

We finally determined (by process of elimination) that I must have spilled some oil when I was topping up the reservoir after my last flight before the "oil spill"...  I had used a disposable paper funnel instead of my usual (and much smaller outlet) plastic one (lost when I moved to the new hangar).  I suspect that while pouring the oil into the funnel, I inadvertently allowed the lip of the funnel to slip outside the oil filler, and that oil ran down the tank side, dripped onto the cowling, then onto the floor.  Since topping off the oil was the last thing I did before turning out the lights and heading home, I just missed seeing the oil dripping onto the floor.  (Of course, my drip pan was 2 inches aft of where the oil dripped off the cowling...  Murphy's law in action.)

Just thought this might have bearing on your issue as well.  Mine wasn't overfilled, but I did manage to overflow the side of the tank opening.  Sigh...

Thanks for the reply James. I have the engine setup to do the crankcase pressure test tomorrow morning. I have a feeling that it will be OK so I will do a full power ground run for a couple of minutes and if clean I will close it up and just go fly a little around the field then check again. I'll report back.

Chris

Crankcase pressure during a three minute full throttle run was around 4 to 5 psi (mostly 4.5 psi). Oil temp only got up to 150F which is much lower than the 266F the manual refers to but that is what my engine will warm up to on the ground with the current outside temps.

The crankcase pressure test setup worked well with the Amazon supplied fitting, a hose and a low pressure gage I have.

After a while warming up and three minutes of full throttle ground run no leaks so will go fly and monitor.

Thanks for the help from the group. I'm certainly learning a lot about these engines through your help.

Best Regards,

Chris 

How do you even manage to run it at full throttle on the ground?  Are you tying the aircraft to something?

Tail tied down and a chock (just one since my airplane only has a one main wheel ?). The Europa build manual actually calls for doing a full throttle run for a couple of minutes to consider the airplane ready for first flight.

So this maybe my final report on this topic: flew for half hour this afternoon. Opened the cowling and not a drop of oil. Go figure. Not complaining. Despite this experience, the engine runs strong and smooth. 

Chris