What was found
LOUD AIR NOISE COMING FROM #1 ENG EXHAUST. WITH APU AIR ON INSPECTED AND FOUND #1 ENGINE PRECOOLER CRACKED AND LEAKING. ADDED PHOTO. REMOVED #1 ENG PRECOOLER ASSEMBLY. REF AMM 36-11-15. SECURED . TAPED OPEN DUCTS, FAMV, AND CONTROL PRESSURE SENSE LINE TO PRSOV. . PRECOOLER, AIRB OFF 25-3611-9-0007 8279 ON 25-3611-9-0007 8258 PRECOOLER, AIRB OFF 25-3611-9-0007 8279 ON 0000 INSTALLED #1 ENGINE PRE COOLER PER AMM 36-11-15-400-803-001.PERFORM LEAK CHECK. OPS CHECKS GOOD PARTS USED: 25-3611-9-0007,QTY :1 ROTABLE PARTS CHANGE WAS INDICATED - TT # 1501971 SN OFF 8279