Project 3C (Cheap Chill Cooling)

Overclockers is supported by our readers. When you click a link to make a purchase, we may earn a commission. Learn More.

DIY water chiller — Doug Getgood

First of all: I am usually a cheap #@$ so and so! When I decided to splurge on a water cooling system last winter, it was (and is!) to be my one really BIG splurge this year!

Now like many of us at OC.Com, I have the Forum areas I follow very closely, but I also check out new posts for interesting stuff frequently, and the setups I’ve seen in the Cooling threads have been both fascinating and piqued my interest in cooling beyond straight “water” (which is actually a mixture of fluids, antifreeze and water being common). But with a budget as tight as mine is right now, I knew there was no way I’d be trying it myself.


A friend of mine asked if I had any interest in an old half-height fridge that was hanging out on his porch, so I decided I would try and make a Water Chiller system. With one stipulation: A budget of $20!!

I read through all the threads on fridge cooling & freezers and started to make some plans:

  • I needed to keep the system as simple as possible, because complexity would add cost;
  • The system had to fit in my desk, because my main computer is in the TV room – this meant it had to be tidy too!;
  • I have spare computers (Surprised?) but this one is my main rig: I use it for work and for crunching for the Overclocker’s Seti Team. So this thing needs to run 24/7 with little maintenance.

I don’t ask much, do I?

On to Project 3C!

The system: AMD Athlon XP 1700@1730, Epox 8KHA+, 512 MB generic RAM and a bunch of other stuff like hard drive, CD/burner, etc. And a Swiftech H202c water cooling kit (external radiator); also DigiDoc5 for temp monitoring and fan control.

I dismantled the fridge, which took about 4 hours total, and then tested it again to make sure I hadn’t broken anything – all good! So on to the next step: testing it with the PC.

I dumped the freezer coil in a 32 quart cooler with 3 gallons of water and tossed my radiator in after 15 minutes. Within another 15 minutes, CPU temp was down 14C! (ambient 20C, case 24C, CPU 35C before, 21C after!).

I took this a sign that it would work and began reading in earnest, trying to figure out what I had that I could use as a fluid reservoir and insulation.

I had planned on using a big Tupperware-like container for the reservoir and insulating with Styrofoam insulation, but the container I had was just too small! So I found the 5 gallon jug style cooler I got last year (and used once!) and found that I could just get the freezer coil to fit. Unfortunately I would have to remove my sliding keyboard tray – Oh well.

I had also planned on using ¼” copper tubing for my heat exchanger, since I happened to have about 15′ left over from some work a few years ago. It turned out to be 1/8″, which is just too small. So the radiator had to go in the reservoir; copper tubing would have consumed my entire budget!

I had no clear plan on materials for insulating the motherboard and waterblock, so once again I hit the OC.Com forums! I got a great deal of help, as always, but conformal spray – which is commonly used to help prevent damage from compensation – was another item that would eat the entire Project C3 budget!

I looked through my piles, and PILES of junk again, but came up with nothing earth-shattering except Vaseline Petroleum Jelly! I seemed to remember something about using that and got confirmation that it would work. I now had all the tools, materials and plans to try and wreck my computer in a whole NEW way!

I used a previously killed mobo to make insulation pads (don’t forget the area in the middle of the Zif socket!) out of old mouse pads, and then I shut the sacrificial lamb down to begin.

I set up the chiller first, to let it start working on the coolant in the reservoir while I insulated the motherboard and waterblock. I applied Vaseline liberally to the back of the motherboard, around, on and in the Zif socket, and in any nooks and crannies between layers of (mouse)pad. I applied fresh Arctic Silver 3 to the CPU, then installed it and the waterblock. I left the top cover for the waterblock off for now so that I could connect the water lines.

I checked the chiller reservoir about this time and was surprised to see that the fluid had not been chilled much yet. Not a great sign! I installed the mobo and connected all the electrical stuff – time for the water lines.

I put the first piece of pipe insulation next to the radiator on both lines and sank it in the reservoir. Running the lines was a bit of a pain, since it had to go through the back of my desk and up to the PC right in a corner of the room, so I finished the insulation with the lines in place.

I seem to have a hard time getting all the air out of my system, so I use a bleed reservoir for a few minutes at a time until they are all gone. With the lines run in, through and behind my desk I really needed it this time! After bleeding the air out it was Time…

Have I destroyed another computer, or will it still work? And will the Cheapo Chiller bring the CPU temp down where I want it?

I am happy to say that the patient lived! At least so far…

CPU temp has only dropped 1C since startup (under full CPU utilization with Seti at Home), and chiller reservoir seems to be hanging at 14C, so this unit may not be enough to really chill my chip, but only time will tell for sure.

Now it’s time for durability testing: If the system can run 24/7 for the next week without trouble, then I can start with volt mods and see how much higher I can OC this chip. My fingers are crossed!

Do I consider Project C3 a success? YES!

The main goal was to see if it was possible to add a water chiller to a water-cooled PC for less than $20, and I have done that. I spent:

  • $6 on Vaseline
  • $3 on a tube of Goop
  • $2 on pipe insulation

and that is IT! Everything else I used was stuff I had laying around the house!

I would like to see better temps and I believe that a long copper heat exchange coil in the chiller reservoir would achieve that – IF I can find some for $9! I’ll run this way for a while and see what happens: If it lives, improvements will be made, but for now I have a computer with no fans running at 1C less than ambient…for $11!

Doug Getgood (aka rogerdugans)


Leave a Reply