As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(AUS) ENGINE OIL SYSTEM THERMOSTATIC OIL COOLER BYPASS VALVE SHAFT NUTLOCK PIN SHEARED. NUT SEPARATED FROM SHAFT AND WAS FOUND IN THE OIL COOLER FLEX LINE. MAIN BODY CIRCLIP GROOVE SHOULDER FAILED FOR APPROXIMATELY 25 PERCENT OF CONTACT AREA.