As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHEN A MECHANIC PULLED THE TOP COWLING TO PERFORM ROUTINE MAINTENANCE, HE NOTED OIL WAS ALL OVER THE FIREWALL AND ACCESSORY CASE. INSPECTION REVEALED THE OIL COOLER WAS LEAKING FROM BETWEEN THE PLEATS. THE EXACT QUANTITY OF OIL LOST IS UNKNOWN.