As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHEN THE EXHAUST PIPES WERE REMOVED TO INSPECT THE EXHAUST VALVES, IT WAS FOUND THAT ALL SIX VALVES ON THE ENGINE HAD EROSION WEAR ON THE STEMS AND THE BACK SIDE OF THE VALVE FACE. THIS IS THE SECOND ENGINE THAT THIS PROBLEM HAS BEEN FOUND ON IN OUR FLEET.