As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIR TURNBACK DUE TO STRONG OIL ODOR IN AIRCRAFT, AFTER BLEEDS WERE TRANSFERRED TO ENGINES FROM APU. LANDED WITHOUT INCIDENT. PERFORMED ENGINE HIGH POWER RUNS WITH ALTERNATING BLEED SOURCES. VERIFIED OIL ODOR. CONTINUED TO RUN SYSTEM TO CLEAR OIL FROM BLEED AIR SYSTEM. ODOR IS NO LONGER PRESENT.