What was found
WHILE CHANGING A CRACKED TURBO INLET (PN K1250860M-105), THE HEAT EXCHANGER WAS FOUND CRACKED. OUT OF 4 AIRCRAFT WITH THIS STC EXHAUST, ALL 4 HAVE HAD THE TURBO INLETS CRACK. THE REPLACEMENTS ARE ASSEMBLED DIFFERENTLY, APPARENTLY TO PREVENT THIS PROBLEM. THE HEAT EXCHANGER IS THE SECOND ONE FOUND CRACKED AT THE WELD LINE WHERE THE NR 6 CYLINDER RISER ATTACHES.