What was found
DURING WALK AROUND CK AFTER ACFT ARRIVAL FOUND PRECOOLER OF RT ENG SQUEALING AND MAKING LOUD NOISE. OPENED R ENG FAN COWL AND THRUST REVERSER COWL FOUND PARTIAL OF THE PRECOOLER OUTLET SCREEN ON THE TOP POSITION WAS DAMAGED. THE LENGTH OF THE CRACK IS ABOUT 12 INCHES. REPLACED WITH NR2 ENG PRECOOLER FROM A/C 2511. CK NO LEAK FOUND. THERMAL INSULATION BLANKET INSIDE LEFT HALF T-R COWL OF RIGHT ENG WAS BROKEN BY LEAKING AIR FROM DAMAGED PRECOOLER. DIMENSION OF THE DAMAGED BLANKET IS ABOUT 12"X12". REPLACED THERMAL INSULATION BLANKET.