As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMB TO FL390, THE NR 1 ENGINE NACELLE TEMPERATURES WERE VERY HIGH AND THE NACELLE LOOP A LIGHT ILLUMINATED. CREW FOLLOWED COM ABNORMAL PROCEDURES AND DESCENDED TO FL350 TO KEEP TEMPERATURES WITHIN LIMITS. FLIGHT CONTINUED WITHOUT FURTHER PROBLEMS. MAINTENANCE INSPECTED ENGINE AND FOUND COMPRESSOR DISCHARGE DUCT CRACKED. DUCT WAS REPLACED AND LEAK CHECKED. THE AIRCRAFT RETURNED TO SERVICE.