As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) THERE WERE 2 SMALL DIVOTS ON THE OUTER EDGE OF THE PISTON SEAL THAT WERE ALLOWING OIL TO GET PAST AND LEAK OUT THE TOP OF THE PROPELLER CYLINDER. THERE WAS NO INDICATION OF A CAUSE FOR THE DIVOTS. NO CONTAMINATION WAS FOUND IN THE PISTON, CYLINDER, OR OIL. THERE WAS NO DAMAGE TO THE CYLINDER WALL WHERE THE SEAL RIDES.