First did you make sure no paper scrap or such was in the fan area?
Next did you replace the fan assembly? Here's the service manual, page and FRU number.
See page 18, "Fan 732068-001"
About 12 dollars at https://www.amazon.com/Generic-Pavilion-736218-001-732068-001-736278-001/dp/B01LVWC81G
I recently have encountered an issue with my HP Notebook Product: HP 15-ba052wm. Whenever I turn on the laptop, the fan becomes so loud that you can hear it in the entire room. I have gone through all of HP's troubleshooting steps for a noisy fan or overheating computer. None of these seem to eliminate the problem.
The only thing that has helped is updating the computer BIOS to the same version previously installed. However, whenever I do update the BIOS the fan only stays normal for a short period. Within the same day, the fan will become loud again and will only go back to normal if I reinstall the same BIOS on the computer again. Does anyone have any ideas on how to fix this? I feel as though I'm going to have to send the laptop to HP as it is still under warranty and I don't want to open it myself.
Thanks for your help!