What was found
AT 10,000FT, THE CREW OBSERVED THE NR 3 ENGINE PARAMETERS FLUCTUATING,FOLLOWED SPECIAL PROCEDURES SHUT DOWN THE ENGINE,DECLARED AN EMERGENCY AND DIVERTED BACK TO PHOENIX. AFTER TAKE OFF, NR 3 ENGINE PARAMETERS BEGAN FLUCTUATING. PERFORMED ABNORMAL PROCEDURE PER AOM. PERFORMED ENGINE SHUTDOWN PROCEDURE PER AOM. R&R OIL COOLER NR 3 ENG IAW B-727 M/M 79-20-1. ALSO R&R NR 3 ENG OIL TEMP BULB IAW B-727 MM 79-34-21 PN 56B17D (TEMP BULB). CKS GOOD IAW ENG RUN JRH 5.2.