What was found
OILY, MUSTY ODOR NOTED WITH APU BLEED TURNED ON. ODOR DISSIPATED WHEN APU BLEED WAS TURNED OFF. MAINTENANCE REMOVED AND REPLACED THE APU AND PERFORMED ECS DECONTAMINATION. APU SHOWED SIGNS OF INGESTION BUT REMOVAL REASON WAS NOT CONFIRMED AND AIRCRAFT CONTINUED TO HAVE REPORTS OF DIRTY, MUSTY ODORS. HEPA FILTERS AND OZONE FILTERS WERE SUBSUEQUENTLY REPLACED AS WELL AS ALL PACK COMPONENTS AND APU COOLING FAN.