As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE COMPLYING WITH LYCOMING MANDATORY SB NR 518A, THE FOLLOWING DISCREPANCIES WERE NOTED ON BOTH LEFT AND RIGHT THERMOSTATIC BYPASS VALVES. INSUFFICIENT CRIMP DEPTH ON CRIMP NUT. CRIMP NUT WAS LOOSE ON SHAFT. EXCESSIVE WEAR NOTED ON BOTH VALVE SEATS.