What was found
IN STRAIGHT AND LEVEL FLIGHT, NR 1 ENGINE OIL TEMPERATURE BEGAN TO CLIMB. AS IT APPROACHED, THE RED LINE WE BEGAN TO MONITOR CLOSELY. WHEN IT WENT ABOVE THE RED LINE, I FOLLOWED CKLIST PROCEDURES AND SHUT DOWN NR 1 ENGINE, MADE RUN ON LANDING. NO OTHER INDICATIONS OF PROBLEMS. MAINT REMOVED AND REPLACED NR 1 ENGINE FOR HIGH OIL TEMPERATURE. ALSO CHANGE THE OIL COOLER AND ITS THERMOSTAT. COMPLIED WITH OPS CHECK BOTH GROUND AND FLIGHT BOTH CHECKED GOOD. AIRCRAFT RELEASED FOR SERVICE.