A friend's laptop's fan has been making louder sound than normal, intermittently. I checked it over a period of time and confirmed that this is so. Sometimes while observing it, the sound increases for a while and then decreases (and then repeats that pattern).
Is this a potential issue? I've advised him to show it to the service center (it is under warranty) but would like to get other opinions on this.
Edit 1: Thanks to all those who answered, so far. I will give him these suggestions and check about the questions mentioned, and then reply again.