What was found
AFTER PERFORMING SEVERAL PREFLIGHTS, IT WAS NOTED THAT THE NR 2 INTEGRATED DRIVE GENERATOR HAD AN INCREASE IN THE FREQUENCY AND QUANITY OF OIL SERVICING. AFTER INVESTAGATING THE CAUSE, IT WAS DETERMINED THAT THE DRIVE END CARBON SEAL WAS LEAKING, ALLOWING PRESSURIZED OIL TO TRANSFER INTO THE NR 2 ENG SYS. A NEW CARBON SEAL WAS INSTALLED IAW THE CMM AND THE ACFT RETURNED TO SERVICE. AFTER THE NEXT FLIGHT, THE NR 2 IDG OIL LEVEL WAS NOTED TO BE LOW AGAIN. THE IDG WAS THEN REPLACED WITH AN O/H RENTAL UNIT. PERFORMED ENGINE GROUND RUN FOR LEAK AND OP'S CHECK WITH NO DEFECTS NOTED. THE ACFT WAS RETURNED TO SERVICE.