As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: PREVIOUS CREW REPORTED STRONG ODOR BURNT OIL ON TAKE OFF AND LANDING\. UPON OUR ARRIVAL AT AIRCRAFT WE COULD SMELL THE ODOR EVEN WITH OUR MASKS ON AND THE CABIN DOOR OPEN. MAINTENANCE HAS ISOLATED THE SOURCE OF THE ODOR TO THE APU. OPEN.