As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) OIL COOLER PULLEY IS MADE UP OF A SPLINE BELT PULLEY WITH A METAL RING THAT IS "STAKED" ONTO THE PULLEY. THE RING WAS FOUND AROUND THE ENGINE OUTPUT DRIVE SHAFT AFTER GROUND RUNNING THE A/C. A NEW PART WAS USED TO COMPARE THE STAKING MARKS ON THE OLD PULLEY. THE NEW PULLEY HAS 4 LARGE STAKE MARKS COMPARED TO 8 SMALLER STAKE MARKS ON THE OLD PULLEY.