As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APPROXIMATELY 45 MINUTES AFTER TAKEOFF, PILOT NOTICED OIL PRESSURE DROPPING. ENGINE WAS SECURED AND PROPELLER FEATHERED WHEN MINIMUM PRESSURE WAS OBTAINED. MAINTENANCE FOUND THE ENGINE OIL OUT TO OIL COOLER IN LINE HAD BROKEN. LINE WAS REPLACED AND OIL TANK REFILLED. ENGINE GROUND RAN, NO LEAKS NOTED. AIRCRAFT RETURNED TO SERVICE.