Question Intermittent Cooling Issue - MSI MAG LIQUID 360 AIO Cooler

Dec 9, 2022
I have an issue with my CPU temps and I was hoping to get some advice.


New build, July this year. I have, amongst other things in there, an i9-12900K cooled by an MSI MAG LIQUID 360 AIO cooler.

About a week ago, soon after starting up, I noticed the machine suddenly get really slow, clock speed drops through the floor and suspect overheating. Correctly, it turned out. I had Core Temp installed from when I built the machine so I started it up and the CPU temps are appropaching 100°C. I turn it straight off.

When I turned the machine on again 3 mins later, everything is fine. CPU runs at 30-40°C when idling as usual and I watch it for the rest of the day (12 hrs running) - no problems.

The same thing happened the next day. First time I put it on, it runs for a minute or so, slows to a crawl, CPU temps up in the 90-100°C range. Off it goes, I let it cool and then start again and it runs for the rest of the day at normal temperature without issue.

After that, I start reading around to see what's going on. My cooler isn't part of the known recall, according to the serial number. I flip round the power connectors for the fans to put the radiator fans on CPU_FAN and the pump on SYS_PUMP (turns out I had them back to front). I check all the fans are running freely. I tune them to spin up faster, at lower temps.

For a few days, it all runs nicely and then again, this morning, I get the same problem. I turn the machine on. Temperature rockets. Of and on again, and it's fine.

I naturally suspect that the pump in the AIO isn't starting up properly and may be failing.

Since I don't want to cook a £600 processor, I have several questions:

  1. Does this diagnosis sound likely?
  2. Is this just what happens when you run AIO coolers for 12 hours a day for 6 months straight? (I expect them to fail first, but not this fast...)
  3. I suspect the pump may not be running at full speed - could it be that sometimes, there isn't enough power being supplied to get it going after it's sat idle? Should I turn it up to max (or will that just wear it out)?
  4. Are there any alternative explanations?
  5. Should I resort to air cooling and higher temps instead?
  6. Should I report this to MSI and ask for a refund?
With appreciation for any advice you may be able to offer,