Introduction: PC External Cooling Tower

Hello, this is my first time write on instructables and

English is not my first language. I’m Thai by the way. My English is bad but I will try my best.

This project is PC external cooling tower via using car radiator.


-Cooling 700w @ differential ambient temp vs water loop temp <10◦c

-Low power consumption 3-6w @ differential ambient temp vs water loop temp < 2◦c and 9-15w >4◦c

-Sensory. if anything go wrong. System will alarm such as pump is not working, sensor missing, leak detect.

-Full close loop no reservoir.

Test result.


First, I don’t want to remove my HDD rack and put water loop instead. I don’t thing put full water loop inside case is good idea. It has many joint and high possibility to be leak. Because the temperature always changes in the loop. The material is going to expand and Shrink all the time. That why I’m using stainless-steel pie instead acrylic pie and stainless-steel pie is good GPU lag support.

Second, It’s easy to maintenance and cleaning.


Q: So do you find that automotive radiators work better than the ones specifically made for PC's?
A: The PC radiator made from copper(only fin. joint made from brass ). But automotive radiator made from aluminium. Thermal conductive Copper 401 Brass 109 Aluminium 205 (W/m.k)

Theory thermal convection Q = h.A.dT Q = Energy(W) h = heat transfer coefficient(W/m^2.k) dT = Ambient surface temperature - water loop temperature

This mean PC radiator quite better than automotive @ Thermal conductive. But if you calculation on surface air drag. Aluminium better then copper. And aluminium quite durable then copper cause aluminium oxide thin layer protection and Full body aluminium NO weak point on joint like Brass + thin. That why i choose aluminium.

If you need to compare efficiency aluminium to copper. aluminium need surface area 1.4-1.5 time of copper. So if you have space for your radiator Aluminium is the best choice but if you have limited space go for PC radiator.

Step 1: Material

- Toyota civic radiator year

2008 $60

- Thermaltake 140mm PC fan with led*4 $60

- 86w 3phase BLDC water pump 1500L/min $60

- Flow sensor(YF-S201)*2 $16

- Temperature sensor (DS18B20)*3 $3.5

- Aluminium Box w115mm*l155mm*h55mm $20

- pipe + silicone tube $55

- LCD, STM32F411 Nucleo, PCB, component $100

- 150w power supply $20

- Aluminum box 1" 6m, Aluminum L 1"6m, Aluminum plate1" thickness 2mm 6m $25

- M8 Bolt stainless steel l30mm drill center hole m5 deep 25mm *5 $ 10 (for temperature sensor)

- 12mm stainless steel tube 6m $11

- Dust filter $10.

- Lots of tool.

$ = usd

Step 2: Mechanic Part

It’s depend on you How to make it suitable to your PC.

- External Cooling Diagram

- PC pipe Diagram

I recommended connect water pipe in parallel not serial. Because connect in serial the flow rate will drop. After I done many tested. Flow rate for each device should be 2-2.5 L/min/device.

Step 3: Electronic Part

I didn’t do circuit design for 5-6 months and I’m forget many things. And I know what I do wrong. So, this just prototype.Send the Gerber file to PCB manufacture and assembly PCB.

Step 4: Program Part

- Download STM32 ST-LINK Utility. From

- Download .hex to Nucleo64

- if you want to see my configuration Download CubeMX and open .ioc