Q: MacBook Pro (Retina, 15-inch, Mid 2015) got noisy and hot

My previous old MacBook Pro did not have any noise and heat issue over 4 years,

but my new one I bought last year has random noisy and heat issues.

I carefully monitored with Activity monitor, but could not really pick a specific app or reasoning,

since it also happened when I just use Word or Safari.

(no other things were going on).

Visited Apple store with this issue several times, and they found some problem in logic board and fans (from the new computer!!!!),

and they replaced them, but still the problem was not really solved.

They asked me to create a new test account to see if this issue comes from my files,

but even with the new account I still had the issue. (That one did not have any of my files)

I did not even install many programs since I don't want to waste any more time on it.

(I had to erase things to prove it's not caused by my software programs)

(Every time when I visit there, I had to leave my computer and it took several days,

it is really inconvenient to study without my computer although I am using other computers at work)

Just FYI, the computer is quite when it's not suddenly noisy and heat up (maybe heat up and then noisy due to the fan)

100% I experience it when I turn on the computer and also some random times that I can't predict.

I am going to visit them again tomorrow and am wondering if any other people experience similar thing.