Fan noise

My cooler (1.5years old) started making a loud fan noise that would go away if I whacked the side of the fridge. Eventually the problem became louder and more persistent. One friend mentioned 'bearings' and another told me to replace the fan. Not sure which to do, and how to get it done (i.e. myself or repair man). Fridge is currently unplugged because the constant noise volume was unbearable. Help!! Wine temperature was never noticeably affected during any of this.