Water-cooled PC Trouble

Overheating computer

A local software business called me today to say that the central processor of their computer was regularly reaching 100°C, even when doing undemanding things such as viewing a text file. The business had a powerful water-cooled system that had been custom-built for them by PCSpecialist. The system was not very old, and had a durable motherboard, but had already suffered from memory and hard drive failures.

New thermal compound

The overheating problem had been reported to PCSpecialist, and they’d sent the local software business a tube of thermal compound for re-seating the water-cooler’s heatsink on top of the central processor. However, the business really was strictly a software business, and the owner was not comfortable working on hardware, which was why he asked me to help. As the problem was urgent, I agreed to look at the system straight away.

Basic cooling system checks

When I arrived on site the customer demonstrated the overheating problem, and the central processor temperature was a serious concern. It was a very hot day, but the cooling system should have been working much better than it was. The radiator fan was working as expected, and the radiator fins were completely free of dust. The water-cooled heatsink itself was plugged into the same 12V DC power source as the radiator fan, so the circulating pump had power.

The heatsink was not installed properly

After those basic checks, I unclamped the water-cooled heatsink from the top of the central processor. The next step was to wipe the old thermal compound from the bottom of the water-cooled heatsink and the top of the central processor. Once the old thermal compound was removed, the customer and I were both flabbergasted to see a plastic label stuck on the copper bottom of the water-cooled heatsink saying ‘Warning! Remove Before Installation!’

Installing the heatsink properly

The people at PCSpecialist had taken no notice of the warning label, and had simply left it in place, reducing the thermal conductivity between the central processor and the water-cooled heatsink to an unknown degree. After removing the warning label and cleaning the top of the central processor with a solvent to remove every trace of thermal compound, I applied the new thermal compound and re-clamped the water-cooled heatsink on top of the central processor.

Cooling system still inefficient

After restarting the system we’d hoped to see a significant decrease in the central processor’s temperature when the system was under load, but it was still overheating to almost the same degree as before. However, it was possible that the water circulation pump was still not working properly. Also the small channels within the water-cooled heatsink could have been clogged up with contaminants.

Never void any warranty

I refrained from taking the water pump apart as it would have voided any warranty that might still be in force, and been too messy to carry out on site (the system was too important to take away for off-site investigation). However, given the reliability of some of the other components that were originally fitted to the system, it wouldn’t have been surprising to find that the cooling pump was at fault.

Poor cooling and premature component failure

Before I left, the customer said that he’d get in touch with PCSpecialist to let them know that they’d failed to remove the protective plastic sheet at the bottom of the water-cooled heatsink, and ask what they intended to do next. Because of their mistake, the system must’ve been running hotter than it should’ve been ever since it was brand new, possibly contributing to premature component failures.