Do heatpipes ever go bad? (Laptop heatsink)

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bobn4burton

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Weird question...has anyone heard of a heatpipe going bad? I guess I already know the answer...if the heatpipe developed any kind of leak then it would become very ineffective.

So here's the situation: I have a Toshiba laptop that has started overheating and turning off. It started several months ago and has just gotten worse with time. As I watch temps on cpu, whenever they reach about 100 degF, the laptop shuts off.

Here's is what I've done:
1. Taken laptop apart, heatsink/internals are all super clean (no dust/dirt/etc).
2. Remounted heatsink with AS5, seemed to help idle temps by 10-15 degrees but load temps spike right up to 100 degF within 1-2 minutes.
3. Fan is working fine. Turns on and speeds up temps start rising.
4. Took shop-vac and blew air through fan/heatsink openings in my garage with ambient temps in the 40 degF range. Doing this kept my full load temps in the 80 degF range and kept laptop from shutting down. (Keep in mind, this was blowing A LOT of air through heatsink air channel AND also throughout the rest of internals of laptop I presume).

My conclusion:
1. It either has to be a bad heatsink/cpu mounting interface (although I've remounted twice...not sure what else I can do to get a better connection)
2. Or, the heatpipe that transfers heat from the main cpu block to the fins portion of the heatsink has become defective and isn't transferring the heat away from the cpu fast enough to keep it cool.

Any ideas on what I could do? Is there anywhere that sells replacement laptop heatsinks?
 
How old is the laptop?

heatpipes in a heatsink/fan setup should last quite a few years.
it's a sealed pipe which means you'd have minimal to no evaporation of the fluid within the pipes.
 
No, heatpipes can not go bad if they remain sealed. Simply because it's usually a fluid, like an alcohol based mixture, that evaporates really easily and then liquifies the further it gets away from the heat source. So no, there is no loss in a sealed system.

However, it sounds to me like the thing isn't even making contact.

My laptop runs at ~80C load inside, however, if I were to go outside with 40*F ambient, my temps drop like a rock. It gets down to 50-55C.

Seems to me like something else is wrong there.
 
bobn4burton said:
Weird question...has anyone heard of a heatpipe going bad? I guess I already know the answer...if the heatpipe developed any kind of leak then it would become very ineffective.

So here's the situation: I have a Toshiba laptop that has started overheating and turning off. It started several months ago and has just gotten worse with time. As I watch temps on cpu, whenever they reach about 100 degF, the laptop shuts off.

Here's is what I've done:
1. Taken laptop apart, heatsink/internals are all super clean (no dust/dirt/etc).
2. Remounted heatsink with AS5, seemed to help idle temps by 10-15 degrees but load temps spike right up to 100 degF within 1-2 minutes.
3. Fan is working fine. Turns on and speeds up temps start rising.
4. Took shop-vac and blew air through fan/heatsink openings in my garage with ambient temps in the 40 degF range. Doing this kept my full load temps in the 80 degF range and kept laptop from shutting down. (Keep in mind, this was blowing A LOT of air through heatsink air channel AND also throughout the rest of internals of laptop I presume).

My conclusion:
1. It either has to be a bad heatsink/cpu mounting interface (although I've remounted twice...not sure what else I can do to get a better connection)
2. Or, the heatpipe that transfers heat from the main cpu block to the fins portion of the heatsink has become defective and isn't transferring the heat away from the cpu fast enough to keep it cool.

Any ideas on what I could do? Is there anywhere that sells replacement laptop heatsinks?
Click to expand...

You sure you're in deg F and not deg C?
 
100 F isn't that hot for a CPU, I don't understand why it would be shutting off at that point. 100f is only like 37c
 
fully sealed unit, I 100% doubt you would have issues with loss of fluid, there are sealed and under a slight pressure, to my knowledge, if there were a loss of fluid, they wouldnt transfer much if any heat, afterall, the liquid is what moves the heat.

Just make sure it is making proper contact, check the heatpipes themselves when it is on(if you can) and see how warm they are actually getting, you could try tightening down the heatink if you can, or even change the thermal paste, if the heatsink is doing its job as it should and they used to little downforce(HS is to loose) or for that matter to little or to much paste/pad and its not conducting the heat well enough, then obviously temps could become and issue. I use MX4 paste, I find it a little better then AS5 and no worries of conduction or anything.

Also 100f is only 37c so I doubt it would shut down at this temp, they are usually speced a little higher then thier desktop equvalents which are 59-75c on average depending on the chip.

I would just make sure the fan that blows air over it is cooling it well enough, make sure heatsink is mounted as it should be, make sure not to much/to little thermal paste, and also, drop the clockspeeds/voltages(if you are overclocking :p) beyond that, maybe send it in for warranty support if you still have it, I doubt you can get a replacement laptop heatsink and if you could, they are probably very expensive just like the displays tend to be. YOu could also get a cooling pad that uses 120mm fans if that is an option, ram more air into it, it might keep it happier :p
 
Sorry guess...it must have been degC. I was using core temp and my temps were approaching the Tj max value it specified of 100 when the laptop shut off.

Sounds like it must be a heatsink/cpu thermal interface problem. Guess I'll play with it again and see.

I did reseat and use AS5. I also tried to bend the little spring restraints just slightly so that it would put a little more pressure...which seemed to help the idle temps a touch but load temps still got too hot.

The heatsink is a solid piece that covers both cpu and NB.

Hopefully I can figure out some way to get a better thermal connection.

Unfortunately the heatsink is under the motherboard and so there is no easy access to it when the laptop is running. I'd like to feel the temp of the cpu block vs the heatpipe vs the fins to see if heat is transferring ok.

I guess my next step is to somehow get access to cpu block and check temps.

If cpu block gets real hot and heatpipe/fins don't heat up much then its probably a bad heatpipe. If cpu block doesn't get too hot, then its most likely a thermal interface between cpu and cpu block issue...
 
I know you said the heatsinkn was clean, but did you remove the fan completely from the assembly and make sure there wasn't a mass built up blocking the air flow.
 
Yep, and like I said, if you can figure out a way to cycle more air into it to blow away the heat that may help, it may have just suffered from running to hot for to long and got damaged. In a certain sence, although temperatures are part of the design element, they seem to be more conerned with "how long can it run before warranty is done". If you changed paste and such, then I would try to get more air into it, a laptop cooling pad may help in this regard, course blowing what you did into it, and if it still shut down anyways, then maybe its just a bad heatsink that is not wicking the heat fast enough, In which case, there is very few options you, as a user, will have, which sux, the aftermarket for latops components for the most part is very limited, and very expensive.

If you wanted to see the temps of heatsink, if you had somekind of digital temp guage with wires, well then you just put that in there, so you could actually see if heatsink is working or not :O, but forcing more air into that puppy is probably easier
 
On one of my Dell laptops I had a THICK thermal pad. The HSF would "bottom out" to prevent overtightening and wouldn't make conctact with the CPU with a "normal" application of grease. I ended up modifying the heatsink to go half a mm further down. If that's the problem you're having, a thin copper shim could help.
 
can also mod it somehow to strap another fan on top of the heatsink, maybe less metal, but would be more air, might make the difference, copper shim, washers, pennies, anything to increase the pressure.

Very good idea Fenris :)
 
Old post, not looking for replys but I figure I will say this for those in the future who do see this.

YES, a laptop heatpipe can go bad. I dont understand why but one side will get hot and the other will stay ice cold. Ive worked on many many laptops (atleast 5000) and only see this 3 times.
 
well nothing is 100% perfectly sealed so the liquid held inside a heatpipe will eventually evaporate and possibly one wick was taking more heat then other, improperly made or whatever and that could cause a "mechanical" failure of the media that allows the heatpipe to function properly, so it would make sense maybe 1 heatpipe was still conducting all/majority of heat so it was hot and other that really was not stayed cold.

I do know some heatpipes that are poorly made can very much be effected by the direction the heatpipe is running by having the liquid level above the heat type deal so it would not "cycle" properly if at all but that would generally cause mass heat on both sides with still cool pipes.

Bad heatsink mounting can cause a buildup of heat and wear out the wick much faster(evaporate faster) though apparently this in theory anyways would also be a very high temperature to do so, I have read somewhere the "average" high TDP heatsink/heatpipe one can expect a decade or more without there being any noticeable depreciation in their performance though I would also imagine with laptops being much more constrained the heatpipe surface may not have the same durability so "should" wear out sooner then say 6mm heatpipes used in average desktop heatsinks.

The liquid is hermetically sealed in the heatpipe so this shouldn't happen, but then again, if the wick was not made properly then it will fail sooner of course, so there would be massive performance drops with some types of heatpipes more then others. but yeh if you said 5000+ to only have 3 have a noticeable issue would assume ~3 years use per, that says they last quite a long time on average ^.^
 
Heh. Usually, in the laptops, it's the fan that fails. But yes, to update my answer from over 3 years ago, I've seen it happen.
 
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