What was found
During Flight # 3407, enroute to Fargo, #3 Engine Oil Pressure low light illuminated. Crew checked Oil Press gauge, indicated no oil pressure in #3 Engine. N1 was about 19%, N2 was about 12%, Airspeed 230 Kts. Windmill time 15 min. Temp at Shutdown normal. Maintenance removed and replaced #3 Engine, PN 2-003-048-15, SN/off P07666, SN/on P07793. Refer to J/C 7100-502 for details. Ops checks good and leaks good. IAW AMM 71-00-00-501.