What was found
BWI - FLT 2662 - UPON CLIMB-OUT FROM BWI, THE NR 1 ENGINE OIL TEMPERATURE WENT INTO THE YELLOW BAND AT FL 160. FLIGHT RETURNED TO FIELD AT BWI AND LANDED WITHOUT FURTHER INCIDENT. TEMPERATURE REMAINED IN YELLOW BAND FOR 12 MINUTES THEN WENT TO THE EDGE OF GREEN BAND ON APPROACH. MAINTENANFE REMOVED AND REPLACED THE NR 1 ENGINE OIL COOLER ASSY AND THE OIL FILTER. OLD OIL FILTER CHECKED GOOD. RAN ENGINE AT TAKEOFF POWER FOR 2 MINUTES AND AT CRUISE POWER FOR 15 MINUTES. OIL TEMPERATURE INDICATION CHECKS GOOD ALONG WITH LEAK CHECK. (M)