Yes you'll need to change the fan. RMA would be best but it your warranty has run out you can find these fans on eBay and there is a very good
dissemble video Yes this fan not working is a very serious thing you need to take care of it.
My CPU hangs at low 40's C same for GPU Ambient Temp here 25C
G752VY-DH72 Win 10 Pro
512 GB M.2 Samsung 960 Pro
1 TB Samsung 850 pro 2.5 format
980m GTX 4 GB
32GB DDR 4 Standard RAM
Z97 PRO WiFi I7 4790K
Windows 10 Pro
Z97 -A
Windows 10 Pro