CPU overheat

real_aurgathor

I’ve just had two over temperature shutdowns at 97°C in the last couple of days, and I’m wondering about possible causes because this is on a computer that I’ve been using for close to 10 years without much of an issue, and it’s very unusual right now since temps are still on the cool side.

It’s a Dell where airflow through the CPU heatsink is provided by a big case fan. The fan is spinning. There was a little bit of dust buildup, but getting rid of that didn’t make much of a difference, which leaves 2 possible culprits:
1) failing heat pipe
2) deteriorating heatsink compound between the CPU and the heatsink

I have never removed the heatsink, so that must’ve been undistrurbed for a very long time, likely since manufacturing, and I would expect that such a failure would show up when temps are close to or above 30 °C.

I don’t usually watch CPU temps, only HDD temps, but I can’t recall seeing anything above 60’s. For comparison, my spare Dell in the same room has CPU core temps in the upper 50’s, but I’m currently watching a video, otherwise temps would probably be around 10°C lower.

How common are heat pipe failures?

Transitman

Thermal paste between the CPU and heat sink can dry out and cause heat related issues.
If you’ve never removed the CPU cooler, then in all probability, your issue lies with the thermal paste failing.
You’ll need to get the heat sink of the CPU, and clean both the CPU and heat sink, and then reapply a good known CPU thermal compound.
Once you do this, you’ll notice the CPU temps far below from what you’re reporting.

Guy54435

Transitman I agree with this assessment, the Thermal Paste might have reached the dry brittle stage of its life.

Jbob

Can we assume you’ve been monitoring the CPU temps since these occurred? And if so what are the CPU temps showing?
Another possibility is the “system” is not increasing the system fans as the temps are increasing thus resulting in higher temps. Dell usually has a built in utility as part of the bios self test to check for fans speed increasing.

dwolfman

For myself, I have to clean out the dust/hair/whatever that builds up on the heatsink fins more often. Which, when you have pets means bits of pet fur is always in the air, even if you can’t see it. Usually about every six months (at most!) I have to get to the heatsink and clean that off. It does make a difference. 🙂

real_aurgathor

Jbob Can we assume you’ve been monitoring the CPU temps since these occurred? And if so what are the CPU temps showing?

Yes, and the current temps don’t make any sense after two shutdowns.

Jbob Another possibility is the “system” is not increasing the system fans as the temps are increasing thus resulting in higher temps. Dell usually has a built in utility as part of the bios self test to check for fans speed increasing.

As far as I could hear, the front fans weren’t running any faster even when the readings were over 90°C, and the heatsink didn’t feel *that* hot. The constant fan speed sure looks like an interesting *feature* since I have another Dell (a server) that most certainly increases fan speed as the temps go up. The fan in question has a 4 pin cable, so it should have both RPM feedback and PWM.

real_aurgathor

Guy54435 I agree with this assessment, the Thermal Paste might have reached the dry brittle stage of its life.

Last summer I’ve had a few days when inside temps were over 30°C and didn’t have any serious issue witch CPU temps, and I don’t think the thermal paste would suddenly start to age this quick.

Some years ago I’ve had to put a small fan on the chipset heatsink (a known issue with this model) but that is most certainly not an issue this time.

Guy54435

real_aurgathor Who knows really, all I know is that something works until it does not work, but 86f isn’t really hot.

Somewhat-Reticent

real_aurgathor suddenly ~~start to age~~

Pop loose ?

real_aurgathor

86°F is not much, but it was 97°C yesterday, and I’m having a hard time to figure out how and why that happened since the heatsink wasn’t *that* dirty. (I’ve seen worse, much worse 😧 )

There are a number of other issues that i need to figure out – first and foremost, why didn’t the fan speed up in unison with CPU temps, and why was only one shutdown recorded in the BIOS when there were two.

real_aurgathor

Somewhat-Reticent Pop loose ?

*Exceedingly* unlikely – there are at least 4 rather substantial screws with #2 phillips heads keeping the heat sink secured, and I never touched those.

While it’s a bit on high side by 5 - 10 °C, it’s more or less operating correctly right now.

HooRU

Heat pipes DO fail, I’ve seen it. If they lose their seal they can fail. I diagnosed it in a laptop for a friend once. Changing it out fixed the problem very well.

If you redo the HS, get some Gelid, there are many good thermal compounds, the Gelid has a very long service life. I’ve never had to redo it.

david3

I haven’t had issues with my cpu shutting down, but it will throttle sometimes if it overheats.

I find that it’s usually dust build-up in the heatsink fins. The only way I’ve found to really clean it is to remove the heatsink and fan from the cpu and clean it well. Either blowing the dust out, or preferably, with water. And then putting it back together with new thermal paste.

That may only last a year, though, and it’s a pain to do. Most of the time, the cpu isn’t that stressed anyway, it’s just if it’s really working hard, like video encoding. So I often just live with it throttling (slower) if I have to encode video.

real_aurgathor

david3

david3 I find that it’s usually dust build-up in the heatsink fins. The only way I’ve found to really clean it is to remove the heatsink and fan from the cpu and clean it well. Either blowing the dust out, or preferably, with water. And then putting it back together with new thermal paste.

I wish I had taken a picture of a heatsink before undusting – it was only a bit dusty, but since I’m unable to get anywhere near to shutdown temps, that’s the only variable that has been changed, so I may need to chalk this up to dust, after all. 😧

Since everything is still in the computer, I only used suction (vacuum cleaner) for cleaning, and I think it did a decent job. Throttling is definitely preferable for shutdown, but aside from replacing the computer (which is already in progress) I my options are somewhat limited,

Here’s the current BIOS log – the shutdown in 2024 was due to the chipset (!!), which was initially a bit perplexing. but pretty obvious after I almost burned my finger on the chipset’s heatsink. 😯 (none of the programs I’ve tried showed the heatsink’s temperature)