What was found
THE FIRST UNIT THAT FAILED WAS AN O/H COOLER, PN 8000074, SN 1041411 MFG. 04/05, INSTALLED 12/01/09 AND FAILED ON 3/19/10. THE REPLACEMENT COOLER WAS NEW WITH SAME PN 8000074 AND SN 1041905 , MFG. 10/09, INSTALLED ON 3/25/10. THE FIRST WAS INSTALLED ON A FACTORY REBUILT ZERO TIME ENGINE. THIS UNIT FAILED AFTER 23.6 FLIGHT HOURS. THE SECOND, NEW COOLER, FAILED AFTER 30 MORE FLIGHT HOURS OR TOTAL ENGINE TIME OF 53 HOURS.