Oil on prop?

Jhogan0101 · #1 01-15-23, 04:09 PM

Im seeing oil on my props. (Not red)
Its not a huge amount.

They were both removed a year ago and the inside “sludge” cleaned out, inner large o ring replaced, props reinstalled.

The oil is engine oil not red and it seems to be coming out from the blade root.

Tape was put on temporarily where prop meets flange so its not from there.

Any ideas?

https://ibb.co/mHVyWDT
https://ibb.co/mNQzQZ4

hharney · #2 01-15-23, 08:41 PM

Pretty common to see oil there in that position. It normally comes from the breather line on the rear engine. If you haven't ever seen this not sure why it is showing all of a sudden.

Jhogan0101 · #3 01-15-23, 08:45 PM

Thanks Herb, i started seeing on the rear and the front.
Its seems to be concentrated on the blade root.

wslade2 · #4 01-15-23, 11:46 PM

Can this be from crankshaft seal?
Interesting that is both front and rear at same time. Are engines of similar time in operation? I had crank seal leak that looked similar.

kbecker · #5 01-16-23, 02:19 PM

Not sure that the rear engine oil breather would be able to get oil on the aft part of the rear propeller.

Ryann · #6 02-08-23, 04:29 PM

The airflow back there by the rear prop is pretty squirrely and random, even going against the slipstream in some places. If I fill to the 8 qt mark, it'll blow some out the breather and end up in all kinds of interesting places that you wouldn't expect. Reminds me a little of a pee tube in a LongEZ I owned somehow putting pee droplets on the front of the canopy even though the tube exited some way down a rear landing gear leg.

Oil (that is not red) near the prop hub could also be migrating back from the crankshaft seal. When my rear crankshaft seal was leaking slightly, I'd usually see a drip waiting to fall from the case right below the rear crankshaft seal, and an oil smudge down the inside of the rear lower engine cowling below it.