Hi,
Here’s a link to the [https://dl.dell.com/topicspdf/g-series-15-3579-laptop_service-manual_en-us.pdf|service manual] for the laptop, taken from this [https://www.dell.com/support/home/en-au/product-support/product/g-series-15-3579-laptop/docs|webpage]
Go to p.28 to view the necessary pre-requisite steps and then the procedure to remove the fan.
Hopefully this is of some help.