Low fan buzz - how to diagnose the problem?

[TOTAL]

I bought x230 whose fan started to buzz loudly soon after.

I was thinking of fan replacement but someone on the forum suggested this might be a paste problem.

How to tell if that is the case? I find the thought of trial-error overwhelming - never disassembled tg

[RealBlackStuff]

Run this program: https://www.alcpu.com/CoreTemp/
It'll tell you how hot your CPU runs.
And get the X230 manual from the HMM link above.
The fan might also be dirty.