B737-800
Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Provided Assistance; Flight Crew Landed in Emergency Condition; Flight Crew Inflight Shutdown; Flight Crew Diverted; General Maintenance Action; General Flight Cancelled / Delayed
Aircraft
In cruise at FL380. Noticed right engine oil quantity indicated 4 qts. Went to QRH and followed procedure. Oil pressure and temperature indications were normal and pretty much matched the left engine. Continued to monitor as directed. Called dispatch on crew phone ( which worked great BTW) and gave him a heads up. Agreed that we would continue with diverts ahead of ZZZ; ZZZ1 and ZZZ2. Quantity indication continued to decrease slowly over the next hour. Pressure and temperature were normal. Approximately abeam ZZZ1 we asked to descend to FL 300 due to turbulence. At idle power; oil pressure and temperature remained normal and basically matched the left engine. However; at level off when power was increased; we noticed that the right engine oil pressure began to noticeably fluctuate and decrease. We immediately [advised] with ATC and began a diversion to ZZZ2. With right oil pressure at or near the red line limit; we elected to shut down the engine. Complied with QRH procedures and executed an ILS/visual single engine approach to RWY 26. ARRF was standing by. We cleared the runway and stopped on the parallel taxiway. ARRF crew checked out the right engine and advised that there were no issues. They followed us to gate A-9. Maintenance met us at the gate and were debriefed.
B737 Captain reported decreasing oil quantity on right engine at cruise with subsequent fluctuating pressure and quantity resulting in an inflight engine shutdown and diversion to make an priority landing.