Are HP Heatsink tubes filled with eutectic fluid?

Are the heatsink tubes on older (8510p) HP laptops filled with something that can leak, and cause them to fail?

I bought an 8510p that was experiencing shutdown/restart loops. I found an obscure web post from somebody who blamed a similar problem on a bad heatsink. To experiment, I tried swapping heatsinks with a working laptop and Voila!, the problem went away on the problem laptop and appeared on the known-good one.

I've taken out the bad heatsink, cleaned it thoroughly, and I can't see any problems at all with it. Some web authorities claim that these heatsink tubes are sealed, and filled with a eutectic fluid.

Does anybody know if this is true?

 

I though all heat pipes had some kind of fluid in them, that's how the heat was transferred away? I didn't think there were any solid or hollow/empty tubes. I could be wrong though, I'm not an expert in that area.

cpu heats up liquid into vapor, vapor travels up to fins, fan cools, vapor condenses into liquid and travels back down to core area again. If there was a small crack I imagine that the vap. could escape in gaseous form and it would reduce the cooling ability of your laptop. Was your laptop overheating with the old heatsinks? I would record the temps of before/after.

 

Once the laptop reaches Windows, the cpu temps are never higher than 52 C, and the gpu never more than 58 C.

The shutdown loops only occur during bootup. They occur almost always after the laptop is warmed up.

If I can get through the boot-up phase, and into Windows, no temp (cpu or gpu) gets over 60C.

I can't figure out why the overheating loop would only occur during boot-up, but I did read a post somewhere that claimed that Windows monitors/controls gpu speed, so gpu overheating can occur in non-windows environments--and not occur in Windows.

I would like to hear from an expert whether these copper tubes are simply thermal conductors/heatsinks, or if they contain a phase-changing material.

 

Yes they do contain vapor and/or fluid not necessarily phase changing, but in many cases yes. Check Wikipedia.

Heat pipe - Wikipedia, the free encyclopedia

" A typical heat pipe consists of a sealed pipe or tube made of a material with high thermal conductivity such as copper or aluminium at both hot and cold ends. A vacuum pump is used to remove all air from the empty heat pipe, and then the pipe is filled with a fraction of a percent by volume of working fluid (or coolant) chosen to match the operating temperature."

 

Great reference read, WingNut! Thanks.

Any HP engineers want to tell us what gas/fluid/liquid got lost?

 

It is a translucent white liquid that is present inside the heatpipes. Had one HP heatsink leak.

 

I opened up the heatpipe on my older BenQ laptops (dead motherboard) and inside it only looked like there were copper fibers going through it.

edit: This notebook computer had a Pentium M 750 CPU. So, made some time around 2005. D;

 

Opened a very, very old Compaq Armada (Pentium III ) and it had some interwoven copper fibres inside the heatsink. No visible liquid or vapour.

 

Most newer heatpipes do have a form of vapor/liquid. And if the quality control isn't great it can affect performance from one heatsink/fan assembly to the next. As an example, I swapped out the HS/F assembly in my DV6z and the new one helped drop cooling by a considerable amount, there must have been something wrong with with my first one. I may cut open the heatpipe and see what's in there. Run some video while doing it to capture if any ghosts escape or anything.

 

I've have fooled with a number of 8510p's, and found curious heat variation between identical machines with the same bios updates, doing similar tasks. When I first get these laptops, they commonly have a thick layer of felted dust between the heasink fins and the fan. Removing that always makes a big difference. Then, despite a clean heatsink/heatpipes, fins, fan, and a new application of Arctic Silver 5, they sometimes still have temperature variations of 20 C.

Heatpipe quality variations would explain that, and a complete loss of coolant would explain that one particular heatsink that produces consistant shutown loops. Of course ghosts are hard to discount, as well.

 

perhaps some are filled with cream cheese, you know HP employee's getting experimental on a friday afternoon

quality control can be so lax on stuff like this its incredible, such a key component. mate of mine used to tell me tales when he worked on Tornado fighter jets, said whenever one came in for repair you could see if it was a 'friday afternoon' job on the wiring. they had one that had to be completely stripped and rebuilt as a result of bodged wiring, and thats on a multi million pound military aircraft! so i think we may struggle on a heatsink a few quids worth of laptop!lol!

 

That sounds legit.
I got my 8510 started for a while by removing the keyboard and having a big fan blowing on it. It would start within 10 seconds of being cooled down.
Turn off the fan, wouldn't boot.
Heatsink, fans etc all appeared OK.
Sill me to try to fix I did the quick way and removed the 2 clamps onto the CPU (or was it the GPU?) lifted it up, squirted more transfer compound in the gap and bolted back together, probably cracked the pipe, and it's no better anyway.
Seems a new Heatsink is in order

 

Given the temperature range, a mix of water and ammonia is a possibility, but given how nasty ammonia can be, it could be something else.

 

..I don't know much about liquid cores in cooling solutions (...even if it sort of strikes me that making these on laptops would be a monstrous waste from a technical perspective. We're likely talking about heat transfer assemblies that work on temperatures that are fairly high, much higher than the boiling point for water, and where the core is coated by very thick and resistant material that can deal with the pressure changes. Things like coolers in.. ships and submarines maybe could be designed to absorb a very high amount of heat before the material stops conducting heat as well. That's probably the most useful application of a liquid coolant component. ..I guess I can see someone might try to use a relatively high density compound of some sort to increase the heat capacity of a copper sink. But... counter-intuitive for the purpose of the thing, and the temperatures are simply too low, and the heat-transfer rate is what's critical...)

...sorry.. babbling again..

But what happens when you have a cheap (nowadays - dirt cheap) heatsink with aluminum coating and a small copper compound core, is that it's possible to burn the copper alloy until it changes heat properties. Either by not venting enough heat, so it gathers too much (and the aluminum alloy insulates it). Or by simply having too high temperature at the end-points (i.e., the goop cakes or there's a too small transfer point). And afterwards, the heatsink looks just fine, but it has about as much conductivity as a bar of steel.

And I think it's possible that if an aluminum array with a copper core (.."copper" in this sense isn't pure, it's a mixed alloy with other materials poured in. But unlike aluminum... is artificial, a layered construction). If that core is heated enough, it's possible that it could "sweat" parts of the compound. Sodium/Natrium, for example. ..salt.

 

Color me skeptical on this.


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Not too sure about the liquid used but there are two parts to it. First is that it needs t use a liquid that will not boil at up to, and/or above, 105c. Doing so will cause less full contact and thermal transfer at the heat plate under extreme loads. The second issue is the pipes usually contain either a positive or negative pressure to tune the evaporation point of the liquid. Once there is a leak you could loose not just the pressure but the liquid as well.

Just loss of the pressure used for tuning the heat pipe could cause it failure to work properly. I do know I had to replace the one on my Gateway system as it was not as efficient as when new.

 

*shrug* Zinc alloys are common as well. Zinc binds with all kinds of material, including salt. Which lowers the temperature limit where the alloy will melt and expand.