What was found
PILOT REPORTED THAT ON CLIMB-OUT THROUGH 6000 FT, THE LEFT ENGINE OIL TEMP ROSE INTO THE CAUTION RANGE. IT RETURNED TO NORMAL AFTER REDUCING POWER, BUT RETURNED TO THE CAUTION RANGE WHEN THE POWER WAS INCREASED TO CLIMB POWER SETTINGS AGAIN. THE PILOT DECLARED AN EMERGENCY AND SHUT DOWN THE ENGINE, AND RETURNED TO BORINQUEN, PR AIRPORT (BQN). MAINTENANCE FOUND A BAD OIL TEMP BULB AND REPLACED IT.