Hydraulic Power pack units are main driving components of driving system. Consisting mainly a motor, a reservoir and a hydraulic pump these units can generate a tremendous amount of power to drive any kind of hydraulic ram. Hydraulic power units are based on Pascal's law of physics drawing their power from ratios of area and pressure. Heating of hydraulic oil in operation is caused by inefficiencies. Inefficiencies result in losses of input power, which are converted to heat. In this work an attempt is made to suggest the best method for cooling of hydraulic system, by studying various methods for increasing heat dissipation in hydraulic system (power pack)