As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) NR 4 CYLINDER, ON INVESTIGATION DURING LEAK, DOWN TEST NOTED LOW COMPRESSION AND LEAKAGE IN EXHAUST PORT. CYLINDER REMOVED AND CRACK FOUND IN EXHAUST PORT. THIS ENGINE TYPE NOTED FOR HIGH CYLINDER FAILURE RATE. CYLINDER SCRAPPED.