What was found
NR 3 ENGINE STARTED SLOWLY LEAKING OIL. AT 1418Z WITH NR 3 OIL QUANTITY INDICATION OF 1 GALLON AND NR 3 OIL TEMP SLOWLY STARTING TO INCREASE, NR 3 ENGINE WAS SHUTDOWN AS A PRECAUTION. AFTER SHUTDOWN, NR 3 ENGINE OIL QUANTITY CONTINUED TO DECREASE TO ZERO WITH WINDMILLING OIL PRESSURE OF 29 PSI. LANDED WITHOUT FURTHER INCIDENT. FOUND NR 3 DIFFERENTIAL OIL PRESSURE SWITCH CRACKED AND LEAKING AROUND ELECTRICAL CONNECTOR. R & R NR 3 DIFFERENTIAL OIL PRESSURE SWITCH IAW MM 79-33-1. NR 3 ENGINE OIL TANK SERVICED TO FULL, 16 QUARTS ADDED. MAIN AND SCAVENGE OIL FILTERS REMOVED, INSPECTED AND REINSTALLED WITH NO DEFECTS FOUND IAW OVHM 72-00. GMM 3.124 COMPLIED WITH. ENGINE RUN PERFORMED BY FLIGHT CREW. ACFT RETURNED TO SERVICE.