daewood frnu201a fan cover in back of freezer fibrates ?

Hi ive just had this side by side fridge freezer for a couple of weeks and it is driving me nuts. There is a fan inside the freezer compartment which has a plastic cover. This fan makes quite a racket when it is cooling. I think it may be the cover vibrating. Is this a common fault with these freezers and how do you recommend i stop it

Thanks

mag
June 2010