What was found
(CAN) DURING ROUTINE ACFT INSPECTION THE NR 3 CYLINDER HAD A READING OF "0" ON A COMPRESSION LEAK DOWN CHECK. UPON FURTHER INSPECTION THE EXHAUST VALVE WAS STUCK IN THE OPEN POSITION. THE CYLINDER HAD APPROXIMATELY 700 HRS ON IT SINCE IT WAS LAST O/H WO 10-1284. CYLINDER WAS REPLACED WITH NEW CYLINDER ASSY. THERE WAS NO NOTE OF ANY ABNORMAL ENGINE ROUGHNESS REPORTED IN THE JOURNEY LOG.