This article is for the reader who is already familiar with the basics of Xbox overheating. He has already tried using his machine in cool, well ventilated locations, away from other sources of heat, limits the hours of usage, keeps the vents clear of dust and obstructions, and keeps the power brick clear of carpeting. I will discuss how a bad connection between the CPU and it’s heat sink or the GPU and it’s heat sink can cause drastic overheating problems.
In the best of circumstances, the Xbox has a cooling system that barely keeps pace with normal heat buildup. Because it has little cooling capacity to spare, it doesn’t tolerate abuse well. Most people would reasonably expect that an Xbox, however badly abused, should take at least a few minutes to overheat.
So if your Xbox gets the 2 red light error (indicating overheating) within seconds of turning it on after a cold start, you may be wondering how this could even be possible.
One reason for such rapid overheating is that either the CPU or the GPU have become detached from their heat sinks. A heat sink is a device that draws off excess heat. In order to do its job properly, the heat sink must be in good thermal contact with the CPU (or GPU as the case may be).
A CPU or GPU can heat up extremely rapidly if it gets no cooling at all. Both of these units consume a lot of power for their size. Only a few seconds would be required for this electrical power to overheat an un-cooled GPU or CPU. This overheating is so rapid that the rest of the console would not even have time to warm up when the overheated CPU or GPU causes the Xbox to shut down. So you end up with a console that still feels cool but is flashing the two red light error.
There are a number of ways that the heat sink can lose thermal contact. Either the thermal paste is extremely old, or too much thermal paste was initially applied, or there’s no paste at all. Perhaps the wrong washers (too thick) were used during the assembly process or the heat sinks were not bolted down properly or perhaps Microsoft left some foil on the heat sink.
When replacing the thermal paste, remember to clean off the old paste first. An alcohol wipe should work for this. Avoid placing too much thermal paste as only a thin film is needed to ensure that there’s no air pockets between the heat sink and the CPU (or the GPU). A good paste to use is Arctic Silver. Keep track of the spacer washers that you remove because they must be placed back during reassembly.
If you’ve never attempted this before but are determined to do this yourself, it is strongly recommended that you get a guide for this kind of repair. Also note that your warranty is voided once you open the console. Good luck.