As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AIR TURN BACK DUE TO SMELL REPORTED IN CABIN & COCKPIT. BORESCOPE INSPECTION OF THE HP IMPELLER AND DIFFUSER PIPES ON ENGINE #1 PERFORMED, FOUND HEAVY SIGNS OF OIL AT HP IMPELLER EXDUCER AND THE DIFFUSER PIPES, ALSO OIL COMES ALREADY OUT FROM DIFFUSER PIPES BETWEEN 9 O AND 10 O CLOCK POSSIBLE REASON FOR SIGN OF OIL CARBON SEAL OF BEARING#5 DAMAGED. ENGINE CHANGED (TC# 20190422009)