As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ACRID SMELL RETURNED ON TAKEOFF AND CLIMB GOT BETTER AT ALTITUDE NOW JUST MILD. SMELL GETS BETTER WITH CABIN FANS OFF AND PACK IN HIGH FLOW. FOUND BRAIDED OIL LUBE LINE AFT SIDE OF GEARBOX ON APU LEAKING OIL INTO AREA OF APU INLET, AND CAUSING OIL SMELL. ACCOMPLISHED PACK BURN OUT ENG RUN, SMELL GONE. CLEANED APU INLET. RESIDUAL OIL SMELL IS STILL REMAINING IN AC. SMELL HAS NOT DISSIPATED ENTIRE FLIGHT. REPLACED RECIRCULATION FILTERS.