CPU Cooler Not Pumping Water

Soldato
Joined
14 Sep 2007
Posts
3,830
Location
West Yorkshire, England
Looking for some advice please. So I'll first list my pc specs below, this was all bought and build by myself in 2015.

Motherboard: Gigabyte Z97X-UD3H-BK
CPU: Intel i7-4790k @ 4.4GHz
CPU Cooler: Cooler Master Nepton 240M AIO Cooling Solution
GPU: Gigabye GTX 980 G1 Gaming
RAM: Avexir Golden Blitz 16GB 2400MHz
PSU: SuperFlower Leadex GOLD 850W

So my pump doesn't seem to now pump any water through the tubes to my CPU, meaning my CPU temps keep rising to 90 degrees or more and I can't really use my PC anymore.

This issue had been present before but after a restart the pump kicks into action again. This time however it doesn't matter how many times I restart, the pump just doesn't work. The radiator isn't warm, all fans in the system all work fine, including the two fans for the coolers radiator,even the Cooler Master logo on the CPU block lights up.

I've always had it set up so my fans are beneath the radiator attached to the top of the case, blowing air up through the radiator. After the issue came about, I changed this after some research to having the radiator beneath the fans with the fans blowing outwards. The air being blown out of these is cold air.

I have the CPU pump plugged into CPU_OPT and the two radiators fans use a splitter and connect to CPU_FAN. I've tried switching these around and it doesn't change anything, I think it even makes more problems for the pump.

I've tried switching them around with putting the pump on SYS_FAN 1, then remaining 3 fans (2 cooler fans, 1 system fan) on the CPU_OPT and CPU_FAN headers. None of doing this have worked so far with making the pump work.

I'm not the best person around a BIOS but I've also changed the fan speeds for CPU_OPT, CPU_FAN and SYS_FAN on full power to see if it would kick in but it hasn't.

Does anyone have any advice / ideas?
 
Sounds like the pump is dead, it's not uncommon, is the AIO still under warranty?

It has crossed my mind, however, I took a break to eat tea and decided to try something different this time and unplugged everything on the extention cord leaving only the PSU plugged in. Booted up and I hear the water get released (finally!). So that was strange, now the PC is booting fine and I'm still none the wiser to what is causing this frequent issue.

So with the pump on _OPT and a manual set speed at 2.50 PWM (maximum it goes to in BIOS), I noticed the fans would ramp up a little and the fan speed for _OPT would display 0. So tried it the other way round again.

So now currently running pump in _FAN and fans in _OPT. Put _OPT back to Normal setting and _FAN on manual at 2.50 PWM. Now it boots up and stays quiet when idling around 30 degrees.

Really confused by the way this is acting but I'll keep an eye on it and see how long it lasts this time.
 
Sounds like the pump is stalling.

What would cause this and can it even be fixed? PC has run okay over the past few days and then again, I woke up to turn my PC on today to find the pump not working.

I'm tempted to just remove it now and replace with the original I received with the CPU. I'll need tools though as I've never removed thermal paste before.

Do you guys use https://www.overclockers.co.uk/arct...-and-surface-purifier-60ml-kit-th-000-ac.html
Or https://www.overclockers.co.uk/akasa-ak-tc-tim-clean-cpu-and-heatsink-cleaner-oa-001-ak.html

Also what thermal paste is recommended? I have the original thermal paste from Intel in the box but not sure if that'll be any good.
 
If you've not done it before, just a little bit of alcohol based cleaner on a lint free cloth when removing the current TIM, don't need to use a lot of force or scrub it with a lot of force or anything, just take your time and keep wiping away the excess until all shiny.

When removing a cooler, back off all the screws a few turns at a time each rather than just taking them out in sequence, stops to much pressure being applied in any one place, and once screws removed do a few light twists with the cooler rather than just pulling it straight off - it helps break bond between cooler and CPU if the TIM is cold and old.
 
Thanks, will have a look into this and get some ordered soon.

So ended up going away in frustration but now returned to the PC, this time it decides to boot up WITH pumping the water... why is it sometimes it won't do this and then other times it will? It can't be because I left my PC, so the CPU cooled down? As the PC was off all night, so it would have been cool this morning.
 
You could try only connecting the pump to the CPU headers and attaching the fans elsewhere, it could be possible that both headers run off of one transistor and it can't handle the load. But I doubt it. More likely that the pump is aging and becoming unreliable. Is it likely that it's getting air locked? i.e. an air bubble in the pump.

Regarding cleaning the chip and cooler surfaces, in a pinch lighter fluid will do for £1 from a newsagent. Nail polish too, bit don't use anything that has oils or moisturisers in. And don't splash that on plastics, it will attack them. I wouldn't buy specialist cleaners unless you're planning on using them regularly. IPA can be had from Maplin or similar, might be labelled as a cleaning product in a can or bottle.
 
You could try only connecting the pump to the CPU headers and attaching the fans elsewhere, it could be possible that both headers run off of one transistor and it can't handle the load. But I doubt it. More likely that the pump is aging and becoming unreliable. Is it likely that it's getting air locked? i.e. an air bubble in the pump.

How would I know if it is? I don't generally have the system rattle, more just it sounds loud without any water pumping through.

I might try the other method also the next time it fails, thanks. Only thing is, I have SYS_FAN 1,2 and 3 but I do have 3 fans. One at the back and two at the front. Will probably need another one of them Y splitter cables to connect two of the fans together.
 
How would I know if it is? I don't generally have the system rattle, more just it sounds loud without any water pumping through.

I might try the other method also the next time it fails, thanks. Only thing is, I have SYS_FAN 1,2 and 3 but I do have 3 fans. One at the back and two at the front. Will probably need another one of them Y splitter cables to connect two of the fans together.
So you hear the pump but water isn't moving? Definitely sounds like an air lock or the pump is jammed somehow. Sorry if I've misunderstood.

I wouldn't worry about the fan cable routing. You can always order a splitter and run one less fan whole you wait - much less critical than having no liquid flow!
 
Well I think I do. What would the PC sound like if the pump wasn't running altogether? From what I can describe, as soon as I push the power button, I know instantly if the water has flowed through as I'll hear the water release and it will be quiet. If it doesn't, it just sounds loud like it's turning on without the water, so the heat just rises and rises. For all I know it could be vibrating but I can't say I notice it, since I don't know what that would sound or feel like.

I guess if I'm still unsure I can try take a video the next time it happens.
 
Well I think I do. What would the PC sound like if the pump wasn't running altogether? From what I can describe, as soon as I push the power button, I know instantly if the water has flowed through as I'll hear the water release and it will be quiet. If it doesn't, it just sounds loud like it's turning on without the water, so the heat just rises and rises. For all I know it could be vibrating but I can't say I notice it, since I don't know what that would sound or feel like.

I guess if I'm still unsure I can try take a video the next time it happens.
If it's louder when the water ISN'T flowing, that's a problem. Unless you mean the fans speed up.

So the main noises to expect are, (in my opinion):

- pump runs, water flows, you hear mild humming and flow noises.

- pump doesn't run, no noise at all from pump or water flow

- pump is running dry, jammed or similar, kind of electric drone. Almost like mains hum - low pitched, kind of jarring noise.

Bear in mind running your pump dry will kill it, fast. Moving the loop around to get air bubbles to shift might undo the jam. Is your loop refillable?
 
Swap out the cooler for the stocker, if that's OK buy a new cooler. Honestly, there's not that much you can do with AIO coolers when they go wrong. There's no point in letting it frustrate you and spoil your day. Pumps are mechanical moving parts and do fail and can fall foul of intermittent problems.
 
Think next week I'll definitely go on to trying air cooling. Had a different issue today pump didn't ramp up like it usually does, runs with a slight humming sound but it seems its running warm water through the pipes. So temps sit around 60/70/80xch2. If I didn't check HWMonitor on every startup, I wouldn't have noticed as it sounded fine.

I'm away this weekend so on the odd chance it could be stuck somewhere, I'll try doing something I read about. I'll prop the front up with a book,so the radiator is tilted slightly.
 
Think next week I'll definitely go on to trying air cooling. Had a different issue today pump didn't ramp up like it usually does, runs with a slight humming sound but it seems its running warm water through the pipes. So temps sit around 60/70/80xch2. If I didn't check HWMonitor on every startup, I wouldn't have noticed as it sounded fine.

I'm away this weekend so on the odd chance it could be stuck somewhere, I'll try doing something I read about. I'll prop the front up with a book,so the radiator is tilted slightly.

if you want to stick to AIO, silent wings are on sale. set the pump to 100% connected to system fan header with warning if it drops to zero RPM, fans connected under the CPU header. and yep- you wont hear the thing running at 100% and why you need to set the alarm lol.

if not, solid air cooler from cryorig,noctua or bequiet
 
I just watched a linus tech video about thermal removal and different products. The last one he mentions is elbow grease and showed how it all came off without the need of any additional products.

Is that a decent way to remove it? Just wondering as I still have the CPU original thermal compound. Would it be safe if I removed the old thermal with elbow grease, using kitchen paper towels? If it'd work I think I could potentially change it today and order more thermal / Isopropyl alcohol for a better job soon.

Or would the age of the paste make getting it off harder?
 
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