Hello ,  my partner’s 2013, Diesel,  A1  has developed a horrible screeching noise after she switches the engine off . 
 

I have located the noise to the radiator fans which are kicking in during this hot weather after she turns the engine off . 
 

I have attached a video of me rotating the fan blades my hand , and there is a clear knocking noise as you try to rotate the blades . They do not rotate freely . I am guessing the bearing is on its way out, or the possibly the fan motor . 
 

Could anyone here help ? Or point me in the right direction. I have only owned Volvos , so I am not used to working on Audi’s
 

I am thinking I can just buy a new OEM fan unit and swap it out for the faulty one , or am I barking up the wrong tree?

Thank you for your help 

It could be the fan or motor. Could balso try a diagnostic check to see if any fault codes flag up