What was found
TAT: 1,999.5 HRS. DURING REGULAR ENGINE OIL CHANGE, MECHANIC NOTICED EXHAUST STAINS ON VACUUM PUMP. UPON CLOSER INSPECTION, FOUND RT EXHAUST STACK CRACKED AND SPLIT. LENGTH ABOUT 4 INCHES BY .50 INCH WIDE. SPLIT WAS DIRECTLY BELOW AREA WHERE ALL 3 CYLINDERS DUMP INTO STACK. STARTED ALONG WELD SEAM.