Cessna 210 Centurion / Turbo Centurion 210C; 210D
Flight Crew Instrument; Flight Crew Private
Flight Crew Last 90 Days 21; Flight Crew Total 6400; Flight Crew Type 4200
Aircraft Equipment Problem Critical
Flight Crew Diverted; Flight Crew Landed in Emergency Condition; General Maintenance Action
Aircraft
In cruising flight at FL190 (19;000 ft) I experienced a rough running engine operating LOP (Lean of Peak). It ran normally ROP (Rich of Peak) indicating a likely magneto issue. I reversed course to return but then I got a low oil pressure reading. I confirmed the low oil pressure with both oil pressure gauges and [advised ATC] requesting an expedited descent to the nearest suitable airport. ATC (Air Traffic Control) was very helpful and I landed at ZZZ without incident. An oil leak was discovered where the oil return line joins the turbocharger.
Cessna P210 pilot reported that an engine oil leak occurred in cruise flight resulting in a diversion.