Question CPU fan can't keep the CPU temp below 100 C when idle ?

Jan 4, 2023
My cpu-fan was really loud so I decided to get a new cpu cooler, but the cpu temperature goes up to 100 C instantly after startup even though I think I installed the new cooler correctly. I cleaned the old thermal paste off and the cooler came with pre-applied paste. When I switched back to the old cooler (with new paste) the problem consists, so I doubt it's a problem with the cooler itself. The cpu fan is working as expected, turning at full speed and being loud. I don't think it's a faulty sensor because there are multiple sensors in the cpu, all showing over 96 C in hwmonitor.

One more thing: I can't get either one of the coolers off the normal way. When I pull up the rotating plastic bits, the cooler becomes loose and can wiggle around. Once it even "bounced" up the moment I pulled up the first plastic-bit, but in order to come off completely, I have to push them out from the backside of the motherboard. Maybe something is broken and the cooler doesn't mount properly? I would appreciate any help, thanks!

Motherboard: ASUS GL12CP
CPU: Intel Core i7-8700
Cooler: Be quiet pure rock slim 2 (It was the best one I could find for the price which still fits in my case)


Welcome to forums and a Happy New Year, newcomer!

Cooler: Be quiet pure rock slim 2 (It was the best one I could find for the price which still fits in my case)
When posting a thread of troubleshooting nature, it's customary to include your full system's specs. Please list the specs to your build like so:

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Both the stock cooler and the pure rock slim use pushpin mounts that can get tricky to install.

Here is my stock instructions on how to get it right:
The stock Intel cooler can be tricky to install.
A poor installation will result in higher cpu temperatures.
If properly mounted, you should expect temperatures at idle to be 10-15c. over ambient.

To mount the Intel stock cooler properly, place the motherboard on top of the foam or cardboard backing that was packed with the motherboard.
The stock cooler will come with paste pre applied, it looks like three grey strips.
The 4 push pins should come in the proper position for installation, that is with the pins rotated in the opposite direction of the arrow,(clockwise)
and pulled up as far as they can go.
Take the time to play with the pushpin mechanism until you know how they work.
Orient the 4 pins so that they are exactly over the motherboard holes.
If one is out of place, you will damage the pins which are delicate.
Push down on a DIAGONAL pair of pins at the same time. Then the other pair.
When you push down on the top black pins, it expands the white plastic pins to fix the cooler in place.
If you do them one at a time, you will not get the cooler on straight.
Lastly, look at the back of the motherboard to verify that all 4 pins are equally through the motherboard, and that the cooler is on firmly.
This last step must be done, which is why the motherboard should be out of the case to do the job. Or you need a case with a opening that lets you see the pins.
It is possible to mount the cooler with the motherboard mounted in the case, but you can then never be certain that the push pins are inserted properly
unless you can verify that the pins are through the motherboard and locked.

If you should need to remove the cooler, first run the cpu to heat it up and soften the paste before shutting down and powering off the pc. That makes it easy to unstick the old cooler.
Turn the pins counter clockwise to unlock them.
You will need to clean off the old paste and reapply new if you ever take the cooler off.
Clean off old paste with alcohol and a lint free paper like a coffee filter.
Apply new paste sparingly. A small rice sized drop in the center will spread our under heat and pressure.

It is hard to use too little.