As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TAKEOFF, CREW EXPERIENCED A STRONG OIL SMELL FOR 10-15 MINUTES. SMELL DISSIPATED SLOWLY TO NO SMELL, CONTINUED UPON DESCENT POWER IDLE. STRONG OIL SMELL RETURNED UNTIL TAXI-IN. APU WAS NOT IN USE. MAINTENANCE ACCOMPLISHED CABIN AIR QUALITY J/C 26L00021001 AND FOUND THE APU TO BE THE SOURCE. FOUND THE APU COOLING FAN ASSEMBLY LEAKING. REMOVED AND REPLACED APU COOLING FAN IAW AMM 49-52-51-000-002-A. ACCOMPLISHED J/C 26L00021002 APU SMELL IN CABIN AND J/C 26L0021004 DECONTAMINATION OF ECS (ENGINES AND APU). ALSO, REPLACED HEPA FILTERS.