What was found
ON PREFLIGHT INSPECTION, THE PILOTS NOTED AN OIL STREAK EMANATING FROM UNDER THE INBD SIDE OF THE RT ENGINE COWL. MAINTENANCE REMOVED THE COWLING AND SAW A GREAT DEAL OF FRESH OIL ALL OVER THE INSIDE OF THE ENGINE COWLINGS. THE TECH RAN THE ENGINE WITH THE TOP COWL, REMOVED AND WITNESSED OIL BUBBLING OUT FROM WITHIN THE PLEATS OF THE RT ENGINE OIL COOLER. THE OIL COOLER WAS REPLACED AND NO OTHER LEAKS OR DEFECTS WERE NOTED. THE OIL COOLER HAD BEEN INSTALLED ON THE ACFT SEVEN WEEKS PRIOR AND HAD ACCRUED ONLY 17.7 HOURS SINCE O/H.