So if you have a fan that’s making a lot of noise it might be a build up of dust on the fan, have you tried to clean it up??
Anyway if it is still doing it after that it might be vibrations. Make sure the fan is correctly seated in the case or on the CPU.
If it is still vibrating maybe it's the case it's self. Check the feet on the case to make sure they are correctly on and are not loose. Loose things vibrate.
Should these not fix it then the Fan it's self might be on it's last legs, and needs replacing.