ABSTRACK SUATU KASUS PADA MESIN MTU 12 4000 V G23 PLTD COT ABEUK DI PT.PLN (PERSERO) RAYON SABANG By MUHAJJIR 1404005010007 One of the performance targets in the Key Performance Indicator is the availability factor (Equivalent Availability Factor (EAF) with a high Equivalent Availability Factor (EAF) value, it is certain that the plant is in a reliable condition by minimizing the disturbance of the SPD unit will increase the EAF value, from that Cot Cotton steam power plant continue to try to minimize by way of troubleshooting problems so that the disturbance can not happen again, one of the disturbances in Sabang PLTD Site one of the Over Heat disturbance caused by the entry of insects, dirt, etc. This causes the radiator work is not maximal to transfer heat to cooling water so it will endanger the system if the SPD continues to operate. the steps to be used in order for the Mining in Machine Radiator MTU 12 4000 V G23 does not occur overheating it will be used the step or method of observation in the field by identifying the problem of damage (damage) that exist in the unit, doing COP so the problem can be solved properly and execute problem solution for SPD not to occur the same disturbance as the problem of the Pendiginan system on Machine Radiator MTU 12 4000 V G23. Keywords: MTU 12 4000 V G23, Radiator, Cooling System Disruption.