As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE IN CRUISE FLIGHT, THE FLIGHT CREW NOTICED OIL COMING FROM THE ENGINE VENT. THE ENGINE WAS SECURED AND THE PROPELLER FEATHERED. AN UNEVENTFUL LANDING WAS MADE. INSPECTION FOUND CYLINDER NR 5 WITH NO COMPRESSION. CYLINDER TO BE REMOVED AND FURTHER TROUBLESHOOTING DONE IF THE CYLINDER IS NOT THE PROBLEM.