What was found
(CAN) THE PILOT NOTICED OIL OVER THE BACK AND RT SIDE OF THE ENGINE AFTER FLYING FOR AN HOUR. THIS HAS BEEN A RECURRING OIL LEAK, WHICH COULD NOT BE FOUND WITH THE ENGINE NOT OPERATING. DURING GROUND IDLE OIL WAS NOTICED TO BE COMING OUT THE SIDE OF THE OIL COOLER FROM A SMALL PIN HOLE, 1 DROP AT A TIME. WHEN THE ENGINE WAS RUN UP TO FLIGHT RPM, A LINE OF OIL STARTED TO LEAK FROM BELOW THE PIN HOLE. OIL COOLER, PN A649-2 IS NO LONGER AVAILABLE FROM MFG AND IS REPLACED BY A NEW STYLE OIL COOLER, PN A749-1.