As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NR 3 CYLINDER FAILED COMPRESSION TEST DURING ANNUAL INSPECTION. BORESCOPED CYLINDER AND COULD NOT FIND OBVIOUS PROBLEM. SQUIRTED SOAPY WATER SOLUTION ON CYLINDER AND DISCOVERED SMALL LEAK COMING FROM ARE BETWEEN UPPER SPARK PLUG HELI-COIL AND COOLING FINS. THIS WAS A NEW CYLINDER WITH 597 HOURS TT ON THE CYLINDER ASSY.