As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE NR 1 ENGINE FUEL - OIL HEAT EXCHANGER HAS A RUNNING LEAK FROM MOUNTING BASE GASKET. ACFT GROUNDED. REMOVED AND REPLACED THE NR 1 ENGINE FUEL - OIL HEAT EXCHANGER IAW AMM 79-21-02-000-801-F00, AND 79-21-02-400-801-F00. ACCOMPLISHED TESTS LISTED IN THE POWERPLANT TEST REF TABLE TEST 3A. LEAK CHECKED GOOD.