Question Can the heatsink somehow evaporate the water of the inside ?

Yes, I've had heatpipes go bad. It's obvious they are made by soldering or crimping one end shut (after filling with some working fluid under partial vacuum) which can crack or leak without showing any obvious signs except they no longer transfer heat.

The working fluid inside is nearly always water for cooling electronics because it's cheap + effective and water works in the temperature range we are interested in (in spacecraft it's ammonia because at the temperatures they are subjected to, water would freeze). These things are supposed to always run at low pressures inside (which greatly reduces the boiling temperature) but if you apply enough heat to them as in these passively cooled Dell GPUs, well then something's got to give:
pu4eqz5nwlp21.jpg

It's a bloated vapor chamber but note the short stub of pipe that was used to fill the water and crimped.
 
Dec 26, 2022
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Yes, I've had heatpipes go bad. It's obvious they are made by soldering or crimping one end shut (after filling with some working fluid under partial vacuum) which can crack or leak without showing any obvious signs except they no longer transfer heat.

The working fluid inside is nearly always water for cooling electronics because it's cheap + effective and water works in the temperature range we are interested in (in spacecraft it's ammonia because at the temperatures they are subjected to, water would freeze). These things are supposed to always run at low pressures inside (which greatly reduces the boiling temperature) but if you apply enough heat to them as in these passively cooled Dell GPUs, well then something's got to give:
pu4eqz5nwlp21.jpg

It's a bloated vapor chamber but note the short stub of pipe that was used to fill the water and crimped.
Can this be from night to day? I mean, suddenly?
Alco, can this be the cause of thermal throttling in CPU playing some videogames of 2003?
 
Considering heatpipes must boil their working fluid to work, the instant that atmospheric pressure leaks into them they stop working, even before they dry out.

Usually it's only one pipe that goes bad so the heatsink still sort of works but poorly. If it's a vapor chamber though, there's only one heatpipe--a very wide one--so if that leaks then the heatsink won't work at all. In the picture we see a very puffed-up vapor chamber which is still working but the contact surface to the GPU die is no longer flat so conducts heat poorly. It's just an example that the solder or crimp isn't necessarily the weak point so it can crack anywhere. Since the working fluid water leaves no oily residue you won't find where that is either (not that it matters since you cannot repair it, only replace).
 
Considering heatpipes must boil their working fluid to work, the instant that atmospheric pressure leaks into them they stop working, even before they dry out.

Usually it's only one pipe that goes bad so the heatsink still sort of works but poorly. If it's a vapor chamber though, there's only one heatpipe--a very wide one--so if that leaks then the heatsink won't work at all. In the picture we see a very puffed-up vapor chamber which is still working but the contact surface to the GPU die is no longer flat so conducts heat poorly. It's just an example that the solder or crimp isn't necessarily the weak point so it can crack anywhere. Since the working fluid water leaves no oily residue you won't find where that is either (not that it matters since you cannot repair it, only replace).
saw on youtube somebody drilled two holes on both ends, injected oil from one hole until oil came from second hole, then soldered both holes...redneck engineering xD