As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PDX - WHEN OPERATING THE APU THERE IS A OILY SMELL INSIDE THE AIRCRAFT. GOES AWAY WHEN THE APU IS TURNED OFF. MAINTENANCE RAN THE APU AND THE AC PACKS FULL HOT AND FULL COLD WITH NO SMELL NOTED. AIRCRAFT RETURNED TO SERVICE. NO PARTS REPLACED.