The fan has recently become quite loud. I've already unscrewed it and removed dust, but it's still quite loud.
A recording with the internal mic: https://drive.google.com/file/d/1AWCTV2fTFP3qXP1JiktnjUWmMY1IpqYU/view?usp=sharing
What could be causing this? It can be heard on the left side of the front panel.