As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE IN CRUISE FLIGHT, PILOT NOTICED SMOKE AND OIL COMING FROM THE TOP COWL LOUVERS OF THE RIGHT ENGINE NACELLE. HE REDUCED POWER, FEATHERED THE RIGHT PROP, AND SHUT THE ENGINE DOWN. THE PILOT LANDED AT SCHEDULED DESTINATION UNEVENTFULLY. MAINTENANCE PERSONNEL FOUND A CRACK (AND SUBSEQUENT LEAK) HAD DEVELOPED WITHIN THE FINS OF THE OIL COOLER.