It might not be a hardware issue...
We've had overheating issues with the laptop at the office.
Screwing them open and blowing out the dust helped a lot.
Because of dust collected in the fan it cannot get rid of the heat.
Be careful if you want to do this yourself though!
I did that and it's still making the same noise, so I am not going to risk it. Will have to bring it to repair and perhaps checking the thermal paste and all the loose screws. I could do that myself but I don't have the proper equipment atm.
I wouldn't do that myself either. I hope they can fix it.