Chosen Solution
I’m thinking of putting new TIM on my rMBP. The ifixit guide goes over this but also talks about replacing the heatsink. Is getting a new heatsink critical or am I okay to reuse the original? Thanks in advance. Also, I’m getting about 50°C at idle and 80+°C at load (close to the TjMax of the cpu)
To start off: I reuse the systems heatsink. But, in some cases the heat sink fails! So its important to first diagnose if the heat sink is good or bad. Doing a good inspection to make sure the heat pipe has not sprung a leak. Before doing anything I look carefully for signs of leakage, staining on the logic board white powder or wetness on the pipe its self besides seeing a hole. If I’m not sure I use a lab grade scale to weigh the heatsink to compare with one that I have already for that series. The lighter one will be the defective one. As to re-applying the thermal paste its not a questions of quantity! Its placement! You don’t need that much, the paste function is to fill the pores of the surfaces of both the chip and the heatsink. You want to make sure the full surface of the chip its self is covered but you don’t want it spilling over! Even here your issue may still be present as to what you are running for apps have a big bearing on the how hot the system is running at. When you are hitting over 90 C you are clearly over stretching what your system can perform. As an example gaming can over stress both the CPU and the GPU logic. Then you need a more powerful system.
Well I have done this repair to a friend’s computer and I destroyed the heat sink (on accident) while trying to take it out because it was really the third computer I have repaired in my lifetime and I was very inexperienced. It might be a good idea to replace it considering it’s relatively low price but it’s totally up to you. Maybe @danj can reccomend against this but from my point of view it’s just better to replace it.
