As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING TROUBLESHOOTING, DIFFERENTIAL COMPRESSION TEST AND CYLINDER LEAKAGE TEST. FOUND CYLINDER LEAKING AIR FROM AREA OF COOLING FINS ON THE EXHAUST PORT. VISUAL INSPECTION FOUND INTERNAL CRACK EXHAUST PORT OF CYLINDER WITH EXHAUST REMOVED.