Hi,
Here’s the [https://download.lenovo.com/consumer/mobiles_pub/lenovo_u330p_u330%20touch_u430p_u430%20touch_hmm.pdf|hardware maintenance manual] for the laptop.
Go to p.46 to view the necessary pre-requisite steps and then the procedure to remove the fan and heat sink assembly.
If the fan is faulty and needs to be replaced the part number is ''90203127''. Search online using the ''part number only'' to find suppliers.