What was found
AFTER LANDING FROM A FLIGHT OF 4 HOURS OVER OPEN WATER, FOUND THE LEFT WING ELEVATOR AND NOSE GEAR DOORS DRIPPING WITH OIL. UPON FURTHER INSPECTION, FOUND THE LEFT OIL COOLER CRACKED ON BASE OF TOP COOLING FIN UNDER THE FITTING BASE. ABOUT 4 QUARTS OF OIL WERE LEFT IN THE ENGINE. DURING INSPECTION, CAN ONLY COME UP WITH THAT MAYBE DUE TO NORMAL ENGINE VIBRATION, THE HOSES AND FITTING LENGTH MAY BE CONTRIBUTING TO A LOAD ON THIS AREA CAUSING THE OIL COOLER, IN TIME, TO CRACK. REPLACED OIL COOLER AND RETURNED TO SERVICE. NO DAMAGE WAS CAUSED TO THE AIRCRAFT.