As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) SHORTLY AFTER DEPARTURE THE FLIGHT CREW NOTED AN ABNORMAL INCREASE IN THE NR 1 ENGINE OIL TEMPERATURE INTO THE YELLOW RANGE, APPROACHING THE RED LINE. THE ACFT RETURNED TO BASE AND AN INSPECTION BY MAINTENANCE DETERMINED THAT THE CAUSE WAS A DEFECTIVE TEMPERATURE CONTROL VALVE IN THE OIL COOLER. THE VALVE WAS REPLACED, EXTENSIVE GROUND RUNS COMPLETED WITH ALL PARAMETERS OPERATING WITHIN THE NORMAL RANGE AND THE ACFT RELEASED BACK TO SERVICE.