Faulty CPU temperature sensor?

[Thark]

So my PC randomly started throttling a day or 2 ago. I started looking for the problem and it turns our my CPU is at a constant (but not fixed) +/-98°C.
When I start up my pc after being shutdown for hours, within 10 seconds the temperature went up to 99°C. Everything still feels cold when I touch the cooling and nothing looks wrong.

 

I did a sensor test with RealTemp, but I'm not to sure what to make of it. As you can see in the screenshots, clearly something is wrong but I can't tell what to do next.

Is my CPU or motherboard broken? Could this still be a cooling or maybe software issue?

What do I do next?

 

Things I tried:
- cleaned and applied new thermal compound
- flashed bios to reinstall latest version
- reinstalled drivers chipset drivers

 

Hardware specs:

Motherboard: Z97 GAMING 5
CPU: Intel Core i7 4790k @ 4.00GHz

CPU cooler: Corsair Hydro H60
GPU: NVIDIA GeForce GTX 970

[FloRolf]

Make sure the pump of your H60 is still running. 

[RollinLower]

i agree with the post above. since the temperature spike is not instant, and the sensor does display other values up untill it sticks at 98 it would seem to be functioning.

place something like a screwdriver or something into your pumpblock and hold it against your ear, that way you can easily see if the pump is running!

[Thark]

42 minutes ago, RollinLower said:

i agree with the post above. since the temperature spike is not instant, and the sensor does display other values up untill it sticks at 98 it would seem to be functioning.

place something like a screwdriver or something into your pumpblock and hold it against your ear, that way you can easily see if the pump is running!

 

56 minutes ago, FloRolf said:

Make sure the pump of your H60 is still running. 

 

Well shit, the pump was indeed not working. I replaced it with the stock cooler and temps are back to "normal".

Thank you both for the fast replies!

[FloRolf]

24 minutes ago, Thark said:

 

 

Well shit, the pump was indeed not working. I replaced it with the stock cooler and temps are back to "normal".

Thank you both for the fast replies!

Here's why you should never go for watercooling for 24/7 operation builds

You should generally always monitor water cooled builds.