As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING DECENT AN OIL ODOR APPEARED IN COCKPIT AND CABIN. SAME SMELL AS ON GROUND. EN ROUTE AT TOP OF FLT. THE ODOR INCREASED ALL THE WAY UNTIL LANDING. REMOVED AND REPLACED THE APU IAW 4901-9401. OPS AND LEAK CHECKED GOOD. RAN PACKS FOR 1 HOUR. NO ODOR NOTED.