This paper describes the application of vibration analysis technique in the diagnosis of machinery high vibration. Data collection on one unit of Cooler Fan of a Centrifugal Compressor in a plant showed that it was vibrating at high amplitudes exceeding the fault limit for the equipment. The highest vibration was recorded at Gear Input Vertical (GIV). Data analysis showed the vibration amplitudes for radial directions tend to be high near the coupling of motorto- gear input. Based on vibration study and proposed recommendation, the remedial action was carried out. The vibration amplitudes showed much reduction and remained within the acceptable limits. © Institution of Engineers, Australia 2012.