What was found
IN CRUISE, THE CREW NOTICE A SUDDEN PARTIAL LOSS OF POWER ON THE NR 2 ENGINE FOLLOWED BY A CONTINUED DECREASE IN PERFORMANCE WITH A CONSTANT FUEL FLOW. THE CREW MADE A PRECAUTIONARY ENGINE SHUTDOWN AND DECLARED AND EMERGENCY THE AIRCRAFT DIVERTED. AN UNEVENTFUL LANDING WAS MADE. MAINTENANCE FOUND A FUEL LEAK ON THE FUEL OIL COOLER. REMOVED AND REPLACED THE FUEL OIL COOLER. OPERATIONALLY CHECKED GOOD. THE AIRCRAFT WAS RETURNED TO SERVICE.