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If the CPU itself is getting hot then I'd take a good look at the CPU Heatsink to see if it's loaded-up with dust. If other things are also running hot then you need to look at your Case's airflow. Ideally, you want a slight negative pressure; more air blowing out then in.
To test the Case's air flow simply run something like Prime95 with the side-panel off and on, allow cooling between testing, and compare. If there's more than a 5C difference then you've got poor airflow. Yes, fans making noise is a sign that they're failing and/or dirty.
Also, clean the CPU's heatsink; compressed air in-part is the solution, pipe cleaner or removal plus a thorough cleaning and when finished by replacing the Thermal Paste is the ideal solution.
When cleaning any fans - hold them in place and don't let compressed air spin them wildly.