Dash 8-400
Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Critical; No Specific Anomaly Occurred Unwanted Situation
Air Traffic Control Provided Assistance; Flight Crew Took Evasive Action; Flight Crew Returned To Departure Airport; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Landed As Precaution; General Flight Cancelled / Delayed; General Maintenance Action
Aircraft
During climb out from ZZZ en route to ZZZ1; we got a chime that quickly went away but then continued to happen. We noticed that the [Engine] #2 oil pressure was fluctuating between the normal indication of about 67 PSI to below 31 PSI. We confirmed the chimes came from the #2 oil pressure warning. We ran the #2 oil pressure warning checklist which later asked if the NP was below 300. It showed 364 and then asked if the NH was below 64%. It was showing between 67% to 69%. We turned back to ZZZ and through out the descent and approach the chime would continue.Causes: Upon landing Maintenance notified us that the #2 Engine was leaking oil and when they opened the nacelle they noticed it had oil all inside the nacelle.
Flight Crew reported an Air Turn Back after #2 engine began to lose engine oil quantity.