As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PDX - STRONG SMELL OF BURNING OIL IN CABIN EARLY IN FLIGHT. DISSIPATED WITHIN TIME. WITH APU, RAN AIRCRAFT BLEED AIR WITH L AND R PACKS FOR 7 HOURS AT DIFFERENT BLEED SETTINGS AND DIFFERENT TEMP AND LOAD SETTINGS. COULD NOT DUPLICATE DISCREPANCY. AIRCRAFT RETURNED TO SERVICE. NO PARTS REPLACED.