As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AN EXHAUST STAIN WAS OBSERVED ON ENGINE COWLING DURING A PRE-FLIGHT WALK-AROUND. CLOSER INSPECTION BY MAINT PERSONNEL DISCOVERED A LARGE CRACK IN THE UPPER SURFACE OF THE EXHAUST DUCT. PART WAS REMOVED FOR REPAIR AND REPLACED WITH A SERVICEABLE UNIT.