How Cheaply Can You Cool a CPU With Water?

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About $135 – 150 – Robert Galewaler

You feel that $250 or more for a kit is too much. Can you cool a CPU for much less?

Lets find out in this guide.

There are things that all cooling systems must have.

  • CPU water block
  • Radiator
  • Fan for cooling
  • Waterpump
  • Tubing
  • Clamps


As everyone who reads knows, there are some very good and some not so good water blocks on the market. What we want is a cheap block, preferably the cheaper the better; however, we also want some bang for that buck we part with.

  • Swiftech Storm Waterblock – $80 if you can find one and you need a higher powered pump
  • Hydrocool Hydro-Stream HS5 – same as above cannot find a price
  • White Water – Actually not made; however it is copied and can be found fairly easily (hint)
  • D-TEK White Water – can be found as low as $24 and works very well
  • Danger Den RBX – can be found for $46 and also works well
  • Danger Den TDX – $49 – This is similar to a White Water block; however you do not need a “Y” to collect the outflow
  • Radiical WHX – 110 Australian dollars
  • Silverprop Cyclone Evolutions V2.0 – $69

All of these are the best of the best blocks on the block.

There are two designs with these blocks for inlet and outlet: All have one inlet but some have two outlets.
The signature of the White water type blocks RBX and D-Tek White Water (WW for short) have this two outlet feature. This means you will need four more hose clamps and four more points of leakage.

No matter which block you pick, if it is one of the above, you are virtually guaranteed a good experience when mated with a good pump and radiator.

In this case we can find a D-tek for $24; however, I believe to enhance the water cooling experience we will go with the Danger Den TDX. Plumbing is as easy as in and out and no “Y” adapter is required.

$49 dollars – CPU Waterblock

The radiator is very important in that it needs to be fairly large and needs to flow both air and water through it fairly easily. There are many water cooling radiators on the market; however, a very good radiator can be found at the auto parts store! You can get a heater core for as little as $16.

I personally like the F-150 cores as they are thick and big. This allows you to mount either a huge fan or two large fans on the core to move air. Water flow through this core is very free flowing also. If you get a prebuilt heater core, try to get a naked core unless you need a good looking radiator rather than an efficient one. You can get a Swiftech MCR120 Quiet Power Radiator for as little as $29 – a fairly good radiator.

You will need to replace the inlet and outlet with some copper tubing and fitting. This requires some soldering and plumbing skills. I believe you will gain more by this than just buying a radiator.
However this is a bit harder than just buying a premade unit.

$29 – Radiator

I am a firm believer that if you can get a big fan and turn it slowly, you get more airflow than a small, fast fan and you will not hear the howl of that small fan either. Please do yourself a favor and go with a minimum of a 120 mm fan or better yet, two.

There are many theories on should you push or pull the air through the radiator. I found in my system that it is better to move the fan at least an inch away from the radiator and pull the air through it. You will need a shroud on the radiator to accomplish this task.

The reasoning behind this is that if you push the air, then the area in the middle of the radiator and the fan receives very little airflow. There is a “cone” of low air flow where the hub of the fan blocks the air. By moving the fan slightly away and pulling the air from the radiator you let the air come through the whole radiator area. A duct can be made from cardboard and duct tape – cheap and effective.

$11 – Panaflow 120mm Medium Fan


Waterumps are used to move water around the circuit – WATERBLOCK to PUMP to RADIATOR. You will find that some pumps are better than others when the pump needs to force water through the radiator, tubing and water block.

Waterpumps are rated by “head” (some waterpump examples HERE). If a pump can push a column of water to 7 feet or more, that is a good head rating. For example, if a Via Aqua can push 370 gallons per hour, how might this be measured? This is measured when the water is at 0 head – basically, no pressure. If you make the pump push the water to three feet, you will get a 100 GPH – more pressure (=resistance), less GPH.. In any cooling system, you want a fairly low total resistance caused by the radiator, tubing and water block(s).

There are now 12 volt waterpumps that work very well; however, their cost is fairly high. Good waterpumps are priced from $55 – 90 dollars. These can be plugged into the same plug as a hard drive and are powered by the power supply in your system. They also have the advantage of being turned on and off with the system.

There are two waterpumps I will recommend – the Maxijet 1200 and the VIA Aqua 1300. Both work very well and I have used the Maxijet for over two years and the Via Aqua for 4 months so far, but it’s still quiet and moves a lot of water. These waterpumps are modified by sealing the housings with epoxy, as I use them in-line, ie not in the water itself.

They also plug into a 120 Volt outlet and run all the time. This is not a bad thing if you run your system all the time. There is a relay that can be used to turn the waterpumps on and off with the system; however, this requires you to rewire the pump. These aquarium waterpumps were designed to be energy efficient and run 24/7/365 to keep those fishes very happy.

$24 – Via Aqua 1300 + $5 for epoxy

Tubing is what makes the water stay where you want it. There is cheap tubing and expensive tubing.
The clear plastic tubing at the home improvement stores can work; however, you have to be very careful not to kink it. It is called vinyl tubing and comes in 3/8 ” 1/2″ or 3/4″ sizes. This is usually less than a dollar a foot. Most people use either Clearflex or Tygon tubing – both are easier to use than vinyl. They both can bend easier without kinking. Ten feet is usually sufficient – however you can get by with as little as 6 feet.

$10 – vinyl or $12.50 – Clearflex

Clamps are needed to connect everything together. There are two types: plastic clamps and stainless steel screw worm gear clamps. Both work well; however, the plastic clamps are easier to use – they also come in colors and look better to boot – none needed total.

$3.00 each – Stanless clamps; $0.75 each – Plastic clamps; $2 – Plastic 1/2″ “T”

I like to use an external system when water is used for cooling. The disadvantages are that two holes need to be drilled into the case. If the radiator and fan are mounted in the case, you need to have sufficient room.

In this system, you need a big Tupperware type container. In this container you will mount the radiator, fan and waterpump. You can also mount the waterpump inside the computer with the fan and radiator in the box.

The easiest way is to measure the radiator and fan and then make holes in the opposite sides to mount the radiator and fan. Connect the fan and radiator to the box. Make sure the fan pulls the air out of the box through the radiator.

You will need two holes for the water into and out of the radiator. A small hole may be needed to run wire from the fan to the computer. Use at least a 14 guage wire and make it as short as possible. Be sure you seal this wire using heat shrink and you will have less problems. If the fan has a molex connector, you can cut the molex from the fan and splice the wire in the middle to lengthen it so it will reach inside the computer. Now when the computer is on, the fans on also.

A small piece of tubing is put on the radiator and then the “T” is installed. Install this so the bottom of the “T” is where you have connected the tube from the box. From the right side of the T, continue to the waterpump. From the left of the “T”, use a foot of tubing and a bottle cap. This should be a high point of the system.

The tubing now goes to the inlet of the pump. This should be low in the box or it can be outside the box behind the system. If you were to fill the tube the water, it will go right into the pump and through the system. Now from the outlet of the pump connect it to the inlet of the waterblock. This is usually the middle of the block. Then from the outlet of the block back to the radiator.

Always test the system outside the computer or with the system off and unplugged – a leak can ruin your whole day. Test for at least 24 hours prior to using the system.

You can use water; however, you will get algae growth and yukies real fast. I suggest some sort of anti-algaecide additive (a couple of ounces of anti-freeze will do) and distilled water as the working fluid.

Total cost, with careful buying, is about $135 to $150.

Good luck!

Robert Galewaler

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