As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: ODOR BEGAN WITH MAIN ENGINES RUNNING ON TAXI OUT. DISSIPATED ON CLIMB OUT. BEGAN AGAIN IN DESCENT APPROX 10K. SEEMED TO BE ONLY WITH ENGINES RUNNING. MAINTENANCE FOUND OIL LEAKING FROM THE BOTTOM OF THE LEFT ENGINE. FOUND LEAK COMING FROM #5 BEARING PRESSURE TUBE AT STRAINER FLANGE. REPLACED O-RING AND ACCOMPLISHED A SATISFACTORY LEAK CHECK PER PPBU MAINTENANCE MANUAL 72-00-50.