As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: STRONG SMELL OF BURNING OIL IN THE ENTIRE AIRCRAFT, SMELL GOT WORSE DURING INITIAL CLIMB OUT. NORMAL CLIMB CONFIGURATION. DECESION MADE TO RETURN TO PHL. AIRCRAFT LANDED WITHOUT INCIDENT AND TAXIED TO THE GATE. MAINTENANCE ACCOMPLISHED GVI AND LEAK CHK OF APU COMPARTMENT IAW AMM 49-00-00. NO LEAKS FOUND.