As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(AUS) ENGINE OIL COOLER BYPASS VALVE (VERNATHERM) FACE BADLY SCORED FROM CONTACT WITH VALVE SEAT WHICH WAS ALSO DAMAGED. FOUND DURING INSPECTION IAW AD/LYC/78 AMDT5 WHICH WAS OVERDUE BY SEVERAL HUNDRED HOURS. PERSONNAL/MAINTENANCE ERROR.