What was found
DFW - INFLIGHT T402/26 RIGHT ENGINE OIL TEMPERATURE WENT OFF SCALE. HIGH DURING CLIMBOUT THROUGH 27,000 FEET AT CRUISE. GAUGE WAS ERRATIC DURING DESCENT. ALL OTHER ENGINE INDICATIONS WERE NORMAL. RETURNED TO DFW AND LANDED WITHOUT INCIDENT. FOUND GROUND WIRE TO ENGINE OIL TEMPERATURE SENSOR WAS LOOSE. SECURED LOOSE GROUND WIRE AND REPLACED TEMPERATURE SENSOR. SYSTEM GROUND CHECKED NORMAL OPERATION.