What was found
CREW REPORTED WHEN APU BLEED AIR IS RUNNING, THERE IS A STRONG OIL SMELL THROUGH THE PACKS. MAINTENANCE ACCOMPLISHED TROUBLSHOOTING CABIN AIR QUALITY JC 26L00021001. APU DETERMINED TO BE SOURCE. FOUND AND CLEANED OIL IN APU INTAKE AND INTAKE PLENUM. POSSIBLE OIL LEAK AT OIL TANK CAP. INSTALLED NEW OIL FILL CAP. ACCOMPLISHED DECONTAMINATION IAW ESC JC 26L00021004. INSPECTED APU FOR OIL AND LEAKS. NO OIL NOTED. NO SMELL NOTED. ACFT OK FOR SERVICE.