What was found
PILOTS & FA REPORT OIL OR DIRTY SOCK SMELL IN CABIN AND FLIGHT DECK AFTER PACKS TURNED ON. SMELL IS MORE LIKE TURBINE OIL, WORSE AT LOWER ALTITUDES AND ON GROUND. GROUNDED - YES. UPON ARRIVAL ON A/C, NOTICED SIGNIFICANT SMELL IN CABIN AND FLIGHT DECK. PERFORMED FIM TASK 05-51 TASK 814, B, (1)~(D). FOUND OIL ON SWAB AND FOUND RESIDUAL OIL ON APU COWL DOOR. PERFORMED ENGINE RUN REF AMM 71-00-00-800-808-F00, OPERATED ENG BLEEDS AND PACKS WITH NO APU BLEED, FOUND NO SMELL. WHEN APU BLEED OPERATED, OIL FUMES/SMELL WAS FOUND. R & R APU ASSEMBLY ON TASK CARD 78349011, HAECO OP 1056 LEAK AND OPS CHECK GOOD.