As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
EWR/BTV---CO3626, CREW REPORTED "AIRCRAFT FILLED WITH FUMES DURING FLIGHT. A CONSTANT LIGHT SMELL OF FUEL/OIL SOMETIMES IT GOT STRONG"...MAINTENANCE TROUBLESHOT TO INTERNAL ENGINE OIL LEAK AIRCRAFT MAINTENANCE FERRIED TO BTV FOR ENGINE CHANGE. REMOVED AND REPLACED ENGINE IN BTV. GROUND RUN OPS.CHECKS GOOD. AIRCRAFT RETURNED TO SERVICE