How to repair GPU fan

A simple clean might be enough, remove the bottom panel of the laptop and take some compressed air and try to remove and dirt and dust that could be blocking the fans. Once you have tried that turn it on and just load up a quick game and see if it helps. If not then the fans will probably need to be replaced, try to find a teardown and re-assembly video and just watch them take off the fans, then put them back. Hope this helps