As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CRUISE, CABIN HEAT SELECTOR WAS PLACED TO THE WARM POSITION. COCKPIT BEGAN TO FILL WITH AN OIL MIST AND SMOKE AND SMELL. HEAT WAS SELECTED BACK TO COLD AND CABIN CLEARED. THIS OCCURRENCE IS STILL UNDER INVESTIGATION. FOUND ENGINE COMPRESSOR SEAL LEAKING. REPLACED SEAL WITH NEW AND NO FURTHER INDICATIONS OF OIL SMELL IN CABIN HAS BEEN DETECTED.