As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING REPAIR OF MASSIVE OIL LEAK ON LEFT ENGINE, FOUND EXHAUST STACK MISSING ON NR3 CYLINDER. STACK BROKEN AT FLANGE AND WAS LYING IN COWL. AIRCRAFT HAD BEEN FLYING THIS WAY FOR SEVERAL HOURS. STACK ON NR2 CYLINDER WAS CRACK MORE THAN 50 PERCENT AT FLANGE. OTHER IMPROPER REPAIRS NOTED ON OTHER EXHAUST PIPES. AC HAD JUST PREVIOUSLY BEEN ANNUALED. NEW PARTS WERE INSTALLED.