As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER A GROUND RUN UP, THE PILOT HAS NOTICED LARGE AMOUNTS OF OIL UNDER THE ACFT ON THE RAMP. FINDINGS WERE THAT THE OIL HAD COME OUT OF THE ENGINE BREATHER TUBE. UPON FURTHER INVESTIGATION, FOUND THAT THE BREATHER LINE WAS ROUTED SO THAT THERE WAS A "TRAP" IN THE LINE, COLLECTING WATER AND FREEZING CAUSING THE CRANKCASE TO PRESSURIZE AND BLOW THE OIL OVERBOARD.