As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING ROUTINE OIL CHANGE, ALUMINIUM WAS FOUND IN ENGINE OIL FILTER. SUSPECTED TO BE PISTON PIN PLUG. CYLINDERS REMOVED AND NR 1 CYLINDER PISTON PIN PLUG FOUND WORN. CYLINDER CHECKED AND FOUND INPERFECTION INSIDE CYLINDER BARREL 1-2" FROM BASE, SUSPECTED CRACK. CYLINDER REPLACED AND ACFT RETURNED TO SERVICE.