What was found
(AIRCRAFT GROUNDED) ODOR EVENT RETURNED, PERFORMED QRH , PACK 2 DEACTIVATED & ODOR WENT AWAY. DURING TSHOOTING AMM 49-00-00-200-811-A FOUND OIL IN FCU DRAIN PORT, R & R APU FCU IAW AMM 49-32-11-000-003-A-400-003-A. APU COOLING FAN HAD OIL ON BOTTOM OF UNIT & AROUND DUCTS, R & R CLEANED APU OIL COOLER FAN PER 3.C IN TC 21-000-002. NO LEAKS NOTED INSIDE OIL COOLING FAN. REINSTALLED COOLING FAN IAW AMM 49-52-51-400-002-A. REMOVED & CLEANED APU OIL COOLER FAN PER 3.C IN TC 21-000-002. NO LEAKS NOTED INSIDE OIL COOLING FAN. REINSTALLED COOLING FAN IAW AMM 49-52-51-400-002-A. DURING REPLACEMENT OF FUEL CONTROL UNIT, NOTED OIL WETTING ON OTBD SIDE OF OIL COOLER UNDER WELD. REPLACED APU OIL COOLER IAW AMM 49-91-44.