As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
REF DF 747, REMOVED HEAT EXCHANGER NEW IN AREA READY FOR INSTALLATION. INSTALLED NEW SEPARATOR ASSY. OPS CHECK GOOD. NO VIBRATION NOTED. REOPENED BY OPBLM ON 17AUG10 DUE TO FOUND PRI HEAT EXCHANGER CRACKED. NR 3 PACK HEAT EXCHANGER INSTALLATION COMPLETED IAW MM.