What was found
ON CLIMB, NR 1 ENG OIL TEMP WAS AT 108 FOR AT LEAST 3 MINUTES. RAN HIGH OIL TEMP CHECKLIST AND REDUCED POWER BY 30%. 2 MINUTES AFTER POWER REDUCTION, OIL TEMP DROPPED TO 107 AND CONTINUED TO DROP ON OUR DESCENT BACK TO DEPARTURE. RETURNED TO FIELD. LANDING UNEVENTFUL. REMOVED FROM SERVICE. INTERROGATED CDS, NO FAULTS CODES LISTED. C/W AMM 05-11-00-992-802, AND MCN 67957-01, ISSUE 2. C/W FIM 79-00-00-810-805. C/W OPS TEST OF THE FLAP DOOR ACTUATOR IAW AMM 79-21-31-710-801, OPS TESTED GOOD. REMOVED AND REPLACED OIL COOLER BYPASS VALVE IAW AMM 79-21-06-000-801, AND 79-21-06-400-801. OPS CHECKED GOOD. LEAK CHECKED GOOD. AIRCRAFT RETURNED TO SERVICE.