What was found
WHILE SERVICING ACFT EXHAUST SYSTEM I LOOKED IN THE EXHAUST PORTS AND FOUND ALL 4 CYLINDERS CRACKED IN THE SAME LOCATION FROM THE EXHAUST SEAT TO THE EXHAUST STUD. THREE OF THE CYLINDERS WERE CRACKED IN THE SPARK PLUG BOSS WITH 1 OF THEM HAVING NUMEROUS SMALL FRACTURES. SN A04-4453, A04-4449, A04-4448, A04-4452. MANUFACTURER HAS AN AD 2007-04-19R FOR CYLINDER CRACKING ON CYLINDERS MANUFACTURED ON 2005 AND 2006. THESE CYLINDERS WERE MANUFACTURED IN 2004. THE FAA NEEDS TO EXPAND THE AD TO COVER CYLINDERS MANUFACTURED IN 2004.