2. Clean the Inside of the Mac
3. Cut Down on Active Apps and Tabs
4. Reset the System Management Controller
5. Run a Fan Test
Another reason why your computer fans are working so loud is that the fans are malfunctioning. To learn if that’s the case, remove all external devices from your Mac and restart it. After your computer restarts, press on the D key to start the Apple Diagnostics program.
The testing of Mac’s fans will only take a minute or two. Just follow the instructions that you see on your computer’s screen. If you see a code on the screen after the test, visit the Apple Support website to see what it means and if the loud fan noise is related to a specific problem.