As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING A ROUTINE 100 HR INSP, A CYLINDER COMPRESSION TEST WAS PERFORMED ON THE ENGINE USING SOAP SOLUTION FOR VISUAL INSPECTION AND DURING THAT CHECK IT WAS FOUND THAT THE NR 4 CYLINDER (SN 4857) AND NR 6 CYLINDER (SN 4864) WERE LEAKING OUT OF THE SIDES OF THE CYLINDER HEADS BETWEEN FINS ON THE EXHAUST SIDE. THE ENGINE WAS APPROACHING TBO AND INSTEAD OF CHANGING CYLINDERS IT WAS DECIDED THAT IT WOULD MAKE MOST SENSE TO CHANGE ENGINE. BOTH NR4 AND NR6 CYLINDERS, PN SA52006-A23P.