As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
OIL FILTER INSPECTION REVEALED EXCESSIVE AMOUNT OF CONTAMINATION. INVESTIGATION REVEALED AIR/OIL SEPERATOR INTERNAL SCREEN COMING APART. YEARS OF VIBRATION MAY HAVE CAUSED SCREEN SEPARATION. FACTORY RECOMMENDS 100 HOURS CLEANING. THERE IS NO WAY TO INSPECT UNIT WITHOUT CUTTING IT OPEN.