Dell Latitude fan making a loud noise

Hey, I’ve got a Dell Latitude that I recently tore down completely. I cleaned everything out, swapped the thermal paste, installed an SSD, bumped the RAM from 4GB to 8GB, and moved over to Windows 10. Despite all that, the fan is still running loud. I’ve been reading up on updating the BIOS, since mine hasn't been touched since 2012.
Anyone have any suggestions or a potential fix? 😁

Updating firmware used to be a huge deal for those laptops that couldn't handle fan speeds properly, causing them to overheat like crazy. That clearly isn't your issue since your machine has been running fine from 2012 until now. The problem here is actually pretty simple, though annoying: it's just material fatigue. The fan is made of plastic that’s worn down over time, and now the ball bearing isn't seated right—it's basically wobbling inside the housing, which creates all that vibration and noise. If the bearing damage isn't too bad, you might get lucky by carefully applying a tiny amount of graphite or some other specialized bearing grease to fill the gaps and balance the rotation. But honestly, you have to be extremely careful; if you overdo it, the spinning motion will just fling the grease all over the inside of the case and potentially cause even more damage.

The best move is to just swap the fan out for a high-quality, quiet one (doesn't matter if it's an OEM part or an aftermarket one).