As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING ROUTINE MAINTENANCE, AN OIL LEAK WAS NOTED BETWEEN THE NR 2 CYLINDER AND THE OIL COOLER. FURTHER INSPECTION REVEALED LOWER AFT THROUGH-BOLT BROKEN APPROXIMATELY ONE-THIRD ITS LENGTH. REPLACEMENT BOLT WAS A SLIGHTLY DIFFERENT DESIGN. ENGINE TIME SINCE FACTORY REBUILD, 128.64.