Chosen Solution
My computer turns off because the fan is not working. Before the failure, it was really noisy. 4MOT/1/40000002: Exhaust I got this message after running the hardware test (using a fan, and under air conditioning). Replacing the computer’s fan should be enough? or does that message implies something else? Should I also look into the heating sink? Thanks in advance!
Don’t bother with the heatsink or thermal paste. The issue you are having with the computer is related to the fan. The computer is getting too hot and without a fan to cool it down it powers off as a fail safe. If there were an issue with the heatsink or thermal paste you would have gotten an error during the hardware test indicating a bad temp sensor or processor overheating. Also, if you do attempt to replace the thermal paste. (which is not necessary at all) make sure you clean off the old paste on the processors and the heatsink with alcohol wipes before applying the new paste.
When you install a new fan, make shure to give the thing a thorough clean with compressed air. On the exhaust side of the fan a lot of dust can accumulate, which accelerates the death of fans. To renew the thermal paste under the heatsink is also a good idea, as the paste dries out with time.
