As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) NR 1 ENGINE OIL TEMPERATURE DURING DESCENT WAS BELOW REQUIRED 66 DEGREES C WHILE IN ICING. NR 1 OIL TEMP APPROX. 10 DEGREES LESS THAN NR 2. NR 1 OIL COOLER BYPASS VALVE AND SLEEVE WERE REPLACED AND TESTED SERVICEABLE. THE REMOVED BYPASS VALVE/SLEEVE SHOWED CHAFE DAMAGE. THE AIRCRAFT WAS SUBSEQUENTLY RELEASED FOR SERVICE.