As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING A00-HOUR INSPECTION OF OIL SCREEN, FOUND NUT ON END OF VERNATHERM THERMOSTATIC VALVE WAS LOOSE. ACCORDING TO LYCOMING SB 518C, THIS PART NUMBER AND SERIAL NUMBER ARE NOT REQUIRED TO HAVE THE INSPECTIONS LISTED TO DETERMINE IF THE NUT IS LOOSE. VALVE WAS RE-WORKED IAW LYC SI NR 1423 AND RE-INSTALLED IN ENGINE ON 6-24-97.