As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) ON START UP A GRINDING SOUND FOLLOWED BY AN ODOR OCCURRED. SHORTLY AFTER STARTUP, SMELL DISSIPATED AND THE FLIGHT DEPARTED. APPROXIMATELY 1 HOUR INTO THE FLIGHT THE GRINDING SOUND RETURNED ALONG WITH THE ODOR. AFTER CONSULTATION WITH MOC THE FLIGHT WAS DIVERTED. RESOLUTION FOUND THE AEVC EXHAUST FAN BEARING BADLY WORN AND GRINDING. FAN REPLACED AND TESTED SERVICABLE IAW AMM 21-26-51, PB 401.