Question Is my liquid cooler dead?

[Airbus580]

So I have this PC for 6 years now, I am using a motherboard Asrock X99 WS and i7-5820K cpu, my liquid cooler is Zalman LQ315. Most of the time my PC is on 24/7 with occasional sleep. So just recently I woke up my PC from sleep, then I notice a CPU temperature spike to the 70Cs-80Cs using Speccy, so I opened my case and see the fan that is connected to the radiator is not spinning, so I figured that's the problem so I replaced it with a spare one that is working. I thought I solved it then I powered up the PC I went to the BIOS to see the CPU temp, but it still keeps rising, it rose to ~90 degrees celsius before I powered off the computer. What seems to be the problem? The pump connector is connected to a CPU fan 3 pin header so in BIOS it shows running at high RPM probably at max speed. Is my liquid cooler dead? Did the water evaporate? If yes what are your recommendations in replacing with a new one? This is my first time replacing a liquid cooler. My CPU case is not that big so I would go with the same size as my current LQ315.

UPDATE: After I left my PC powered off for a couple of hours I powered it up again and to my surprise the CPU temp went back to normal. I am glad that it got fixed but what really caused it?
Additional info is that during that offline time I also removed a busted case fan (top). Could that be the culprit? Could a busted case fan cause an incorrect (rising) high CPU temp reading?

 

[CountMike]

So I have this PC for 6 years now, I am using a motherboard Asrock X99 WS and i7-5820K cpu, my liquid cooler is Zalman LQ315. Most of the time my PC is on 24/7 with occasional sleep. So just recently I woke up my PC from sleep, then I notice a CPU temperature spike to the 70Cs-80Cs using Speccy, so I opened my case and see the fan that is connected to the radiator is not spinning, so I figured that's the problem so I replaced it with a spare one that is working. I thought I solved it then I powered up the PC I went to the BIOS to see the CPU temp, but it still keeps rising, it rose to ~90 degrees celsius before I powered off the computer. What seems to be the problem? The pump connector is connected to a CPU fan 3 pin header so in BIOS it shows running at high RPM probably at max speed. Is my liquid cooler dead? Did the water evaporate? If yes what are your recommendations in replacing with a new one? This is my first time replacing a liquid cooler. My CPU case is not that big so I would go with the same size as my current LQ315.

UPDATE: After I left my PC powered off for a couple of hours I powered it up again and to my surprise the CPU temp went back to normal. I am glad that it got fixed but what really caused it?
Additional info is that during that offline time I also removed a busted case fan (top). Could that be the culprit? Could a busted case fan cause an incorrect (rising) high CPU temp reading?

If your pump is connected to CPU_FAN, where are radiator fans connected to ?
A sentence from here https://m.hexus.net/tech/reviews/cooling/76709-zalman-lq315/

Once everything is in place, a three-pin cable is used to power the pump (this can be connected to any motherboard fan-header and should be set to operate at 100 per cent) while the 120mm fan attaches to a four-pin header.

 

[Mr.Spock]

you should connect the radiator fan to the CPU FAN header or CPU AUX so it reacts in proportion to your CPU temp.
otherwise it only works off ambiant temp so your temps may rise a bit before the FAN kicks in depending on your SYS/CHA fan curve

 

[Airbus580]

you should connect the radiator fan to the CPU FAN header or CPU AUX so it reacts in proportion to your CPU temp.
otherwise it only works off ambiant temp so your temps may rise a bit before the FAN kicks in depending on your SYS/CHA fan curve

If your pump is connected to CPU_FAN, where are radiator fans connected to ?
A sentence from here https://m.hexus.net/tech/reviews/cooling/76709-zalman-lq315/

Once everything is in place, a three-pin cable is used to power the pump (this can be connected to any motherboard fan-header and should be set to operate at 100 per cent) while the 120mm fan attaches to a four-pin header.

Yes the radiator fan is connected to the CPU fan 4 pin and the pump is connected to the CPU fan 3 pin as per the manual instructions. But the high CPU temp problem got fixed after I removed the other broken case fan (was placed on top of the CPU case), but was that really the cause? Can a broken case fan that is connected cause the motherboard an incorrect reading or actually make your CPU temp spike to such high temps?

 

[drea.drechsler]

Yes the radiator fan is connected to the CPU fan 4 pin and the pump is connected to the CPU fan 3 pin as per the manual instructions. But the high CPU temp problem got fixed after I removed the other broken case fan (was placed on top of the CPU case), but was that really the cause? Can a broken case fan that is connected cause the motherboard an incorrect reading or actually make your CPU temp spike to such high temps?

How old is your AIO cooler? I really like my AIO but the sad thing about liquid coolers is they aren't maintenance free, and yet almost no AIO coolers are maintainable. The tubes are permeable and liquid will evaporate through them with time, some much faster than others depending on the material used for the tubing. Refilling them is difficult even if the manufacturer left a refill port.

But even more troublesome is gunk frequently builds up on the microfins milled into the water block cooling plate which blocks heat transfer. The usual life is about 5 years but many go much faster, sometimes as fast as one-two years if the mfr. didn't use proper anti-corrosive and biocide in the liquid. Removing the cooling plate (for cleaning) isn't easy and hard to get sealed up properly after.

 

[geofelt]

What is your case and fan arrangement?
Any cooler needs a good source of fresh air to let it do it's job.
Over time, air creeps into the fluid through the hoses.
This air will migrate to the top of the system.
Normally, not a big issue, so long as the pump is not the highest point.
AIO coolers do not last forever and they can not be maintained.
Your aio with a 120mm fan is very weak and not the best for your processor.
It is somewhat comparable in performance to a air cooler with a 120mm fan like the noctua U12s.
I suspect you could do much better replacing your aio with a simple air cooler like the noctua NH-U15s.
Here is noctua's suitability chart for your processor:
https://ncc.noctua.at/cpus/model/Intel-Core-i7-5820K-253

 

[Airbus580]

How old is your AIO cooler? I really like my AIO but the sad thing about liquid coolers is they aren't maintenance free, and yet almost no AIO coolers are maintainable. The tubes are permeable and liquid will evaporate through them with time, some much faster than others depending on the material used for the tubing. Refilling them is difficult even if the manufacturer left a refill port.

But even more troublesome is gunk frequently builds up on the microfins milled into the water block cooling plate which blocks heat transfer. The usual life is about 5 years but many go much faster, sometimes as fast as one-two years if the mfr. didn't use proper anti-corrosive and biocide in the liquid. Removing the cooling plate (for cleaning) isn't easy and hard to get sealed up properly after.

What is your case and fan arrangement?
Any cooler needs a good source of fresh air to let it do it's job.
Over time, air creeps into the fluid through the hoses.
This air will migrate to the top of the system.
Normally, not a big issue, so long as the pump is not the highest point.
AIO coolers do not last forever and they can not be maintained.
Your aio with a 120mm fan is very weak and not the best for your processor.
It is somewhat comparable in performance to a air cooler with a 120mm fan like the noctua U12s.
I suspect you could do much better replacing your aio with a simple air cooler like the noctua NH-U15s.
Here is noctua's suitability chart for your processor:
https://ncc.noctua.at/cpus/model/Intel-Core-i7-5820K-253

The same time my PC was prebuilt on 2015, it's around 5.7 years now to be precise. My case is cheap (https://aerocool.io/product/gt-a/ and a broken one at that the two front USB 2.0 ports weren't working from the start lol, I know I should've got it replaced...), I didn't really have any CPU temp problems until now, and occasionally I clean the dust off around the radiator. I bought cheap case fans (placed on top and another around the front area for the hard drive) around 2016.
I replaced the broken radiator fan with a working one but the rising CPU temp didn't get fixed so a couple of hours later (after contemplating and researching on whether to buy a new cooler) I also tried unplugging the broken top case fan that was still connected to the motherboard, and I booted up, went to the BIOS and the rising CPU temp (~90Cs) was gone, it was now hovering over the 30Cs. I really can't explain how could that broken case fan cause a "bug" in CPU temp reading. But then I also realized after checking all my case fans, one of the two front case fans for the hard drive has also stopped spinning but I have not removed it yet.