Cessna 402/402C/B379 Businessliner/Utiliner
Troubleshooting
Aircraft Equipment Problem Critical
Flight Crew Landed in Emergency Condition; General Maintenance Action
Aircraft; Weather
At the above time date and location the oil pressure was observed to be slightly above the normal operating range. This was not completely unusual in extremely cold conditions and the aircraft had remained outside on the ramp at ZZZ overnight in -13c temps and was extremely cold soaked. Within a few minutes it returned to the normal operating range; but very slowly was continuing to decrease. The pressure dropped below normal operating range Station Operations was contacted and relayed a message to and from Maintenance. They suggested we just follow flight manual guidance. The pressure slowly continued to drop. Oil temp and cylinder head temps were all normal. The Quick Reference Handbook was reviewed. As we were considering a precautionary shut down the engine failed. The QRF immediate action items were performed followed by the QRF checklist. [ATC was advised]. We were very near the top of descent for landing at ZZZ1 and the safest course of action was to continue as planned. I took over the flying pilot duties and made a normal visual approach and landing. We requested a stop on the runway and were towed off the runway to the hangar.
C402 Captain reported a loss of oil pressure that resulted in an engine shutdown and diversion.