As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING A SCHEDULED INSPECTION, THE LOWER FORWARD CRANKCASE THROUGH-BOLT ON NR 6 CYLINDER WAS FOUND COMPLETELY SEPARATED. FURTHER INSPECTION FOUND THE BOLT IMPROPERLY INSTALLED. THE BOLT FAILED IN THE O-RING GROOVE LOCATED IN THE MIDDLE PORTION OF THE BOLT. THIS ENGINE WAS A FACTORY REMANUFACTURE WITH 77.2 HRS SINCE INSTALLED ON THIS AIRCRAFT, P/N 641931981.