What was found
DURING CLIMB FROM LAX, THE NR 2 ENGINE OIL TEMP KEPT CLIMBING HIGHER AND HIGHER. CLIMBED PASSED 107 DEG C AND TOPPED OUT AT 113 DEG C. PERFORMED THE EM CHECKLIST WHICH CALLED FOR CLOSING THE INTAKE BYPASS VALVE BUT THAT DIDN'T HELP. WASN'T UNTIL LEVEL AND OAT BELOW FREEZING THAT TEMP STARTED TO DROP. MAINTENANCE C/W ENGINE INSPECTION AFTER SUSTAINING RUNNING AT AN OIL TEMP OUTSIDE SPECIFIED LIMITS IAW Q400 AMM TASK 05-53-00-210-814. NO FAULTS OR CONTAMINATION NOTED. REMOVED AND REPLACED OIL COOLER FLAP ACTUATOR IAW Q400 AMM 79-21-31-000-801. REMOVED AND REPLACED OIL COOLER BYPASS VALVE IAW Q400 AMM 79-21-06. GROUND RAN. LEAK AND OPS CHECKS GOOD. OIL TEMP STAYED IN SPECIFIED RANGE. AIRCRAFT RETURNED T