It has started making a very loud noise. I have taken it out and checked it and it is the fan to cool the case. It has a funnel on one side between it and the outer case and it has a collar that attachs to a circular fin on the other side.
Are you talking about the side fan? Mind taking a pic?
The fans probably dying due to a bearing, you could try to fix it, but a new fans only $2 bucks anyways.