I built this PC in November 2024 with a Ryzen 7 9800X3D, MSI B650M Project Zero motherboard, MSI MAG E360 liquid cooler, and MSI MAG PANO M100R PZ case. The CPU is running without overclocking or PBO, with EXPO enabled and the latest BIOS installed.
For roughly 20 months, temperatures were normal, reaching about 72°C during demanding Cinebench R23 and FurMark tests. Recently, temperatures began jumping from the 60s into the high 70s or low 80s during game cutscenes. When I ran a stress test, the temperature climbed from 50°C to 95°C in under 10 seconds.
I replaced the thermal paste with Arctic MX-7, thoroughly cleaned the cold plate and CPU with isopropyl alcohol, and remounted the block evenly in a cross pattern. That made no difference—the CPU still reaches 92–95°C almost immediately.
While the CPU was overheating, the radiator fans were blowing cool air, both tubes felt cool, and I couldn't feel any vibration or fluid movement from the pump block. The copper cold plate also has some discoloration. BIOS and monitoring software still show an RPM reading.
Does this sound like a failed pump, a blockage, or possibly a coolant problem? Can a pump's impeller be seized or broken even when an RPM signal is still reported? I've decided to send the cooler in for warranty service, but I'm curious whether these symptoms conclusively indicate a circulation failure. A refund would be preferable since the same cooler now costs about 20% less, and I'm also considering switching to a different cooler afterward.
3 Answers
A pump can report an RPM signal even if the impeller is seized, damaged, or barely moving, so the software reading isn't definitive. A dead pump is more likely here than a leak, especially since there are no signs that the radiator is receiving warm coolant. If the warranty claim is approved, a refund and a quality air cooler would eliminate several possible failure points.
This strongly indicates that coolant is no longer circulating. A poor mount or bad thermal paste can cause high temperatures, but they wouldn't explain a radiator that stays completely cool, cool tubes, and no noticeable pump vibration after the cooler worked normally for so long. The likely causes are a failed pump, a blockage, or severe coolant loss.
You can check that the pump cable is connected properly, set its header to run at full speed, and verify the reported RPM in BIOS or HWiNFO. However, an RPM reading only confirms that the tachometer signal is active; it does not prove that the impeller is moving coolant effectively. Avoid further stress testing and proceed with the warranty claim.
A sudden change after many months of normal operation usually means the pump has failed or a blockage has developed in the loop. Cool radiator air means the heat isn't reaching the radiator, so replacing the thermal paste won't solve it. At this point, replacing or returning the cooler is the sensible option.
I sent it in for warranty service and received approval for an exchange or return. I'm now looking at Arctic models as possible replacements.