As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
REMOVED PROPELLER TO REPLACE CRANKSHAFT SEAL. FOUND CRANKSHAFT FLANGE SEVERELY CORRODED. REMOVED ENGINE FROM SERVICE FOR CRANKSHAFT REPLACEMENT. ENGINE HAD BEEN OVERHAULED BY AN 'IA' JUST 75 HOURS AND 3 YEARS PREVIOUS TO THIS DISCOVERY. SUBMITTER BELIEVES CORROSION EXISTED AT THAT TIME.