What was found
ROC/EWR - FLT 3625 - AFTER TAKEOFF IN CRUISE, CREW NOTED NR 1 ENGINE OIL PRESSURE LOW AND LOOSING PRESSURE. SHUT DOWN ENGINE AND RETURNED TO ROC UNEVENTFULLY. UPON INSPECTION OF THE ENGINE IN ROC, FOUND B-NUT LOOSE. RESECURED B-NUT AND SERVICED ENGINE WITH OIL, LEAK AND OPERATIONALLY CHECKED SATISFACTORY. ACFT TT: 14,935.5 HOURS. ACFT CYCLES: 19,104.