Van's Air Force
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Oil Leak O-320
- Thread starter l-2
- Start date
Depends on where the leak actually is. If it is the gasket between the sump and the engine case, the sump can be removed with the engine on the airplane.
It could also be the cyl oil return line coupling hoses (just above and fwd of where the #4 intake tube couples to the sump. This is a very common oil leak location.
An actual oil leak at the intake tube coupling is highly unlikely. There is no oil path to there unless the sump is damaged or cracked (in which case you would likely have symptoms of other problems also)
Thanks for the reply. This is the strangest thing. This thing leaks without the engine running. If fact the engine has not ran since Saturday when I discovered the leak. Everything above the sump is dry. I did carefully check the oil returns on all cylinders etc. If I wash the area off with solvent and dry it with air and return the next morning I have oil drips hanging off the bottom of the sump in a couple of places, oil has dripped onto the left exh pipe and ran down to the rear exh hanger and pooled there a bit. Not to mention small puddles on the floor. The sump has not been damaged, it was new with the engine. My A&P friend is under the weather and I have not bothered him with this but I hope he gets back on his feet and looks at this for me. I am considering putting dye in the oil as a way of confirming the source of the leak. I just don't want to start taking things apart and throwing parts at it until I am 100% sure.
DanBaier
Well Known Member
Suggest that before dye, you try cleaning the area well and using some spray foot powder over the suspected leak area. The source of the leak will show up well.
The advice about checking the runback tube connections is good - check for the clamps being tight and the hoses not being damaged (ie., cracked).
Dan
The advice about checking the runback tube connections is good - check for the clamps being tight and the hoses not being damaged (ie., cracked).
Dan
On my Lycoming sump, I believe that the intake tubes are pressed in to the sump(interference fit). It wouldn't take but .001" or so out of round on the machined hole in the sump to create a leak. If I remember correctly, those tubes sit below the oil fill line and therefore capillary action will do it's thing. Try cleaning well where that tube goes into the sump and putting some talcum powder or dust on the area. Come back in a day or two and you'll know if that is it. Good news is that the fix is pretty easy. clean the area real good and apply some epoxy or JB weld to seal it off.
EDIT: disregard. I just recalled that my tubes inside the sump were cast and the casting continued through the sump wall. My next guess would be with the previous poster: Oil return stub coming from the lower engine case.
Good luck,
Larry
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