Why do you have to bleed PC water cooling setups?

[ssjwizard]

Generally in normal automotive usage the coolant also acts as a lubricant on the water pump. The pumps we run in PCs are designed not to require additional lubrication.

@ATMNDIDE actually glycol raises the boiling temp of water also. Race cars as far as I know run straight water for the very slightly higher thermal performance. Since their engines are being pushed significantly harder they need every single W of transfer possible to maintain them.

Here are some graphs and a somewhat decent description of what PG/H2O mixtures boil and freeze at.
http://hellafunctional.com/?p=629


Copper Sulfate is a biocide but honestly its super mild. Its sufficient for your cooling loop and the worst thing that's going to happen if you spill it on yourself is mild skin irritation, and it needs to be pretty strong mixture for that to happen. Its perfectly safe to dispose of in any number of ways. Honestly there's probably more copper in my ground water than we add to our loops.

Pure silver is also a biocide, though it is subject to corrosion, but with fairly frequent coolant changes you can mitigate any clumping that may occur.

 

[JeremyCT]

That's backward. Coolant lowers the freezing point and boiling point simultaneously. Why else would race cars run straight water?

No, I'm absolutely correct on that count. Adding salt to water does the same. Boiling point goes up, freezing point goes down.

Race cars use pure water because a coolant leak of any kind on track is extremely hazardous for the other racers. Ever notice how slippery a 50/50 mix feels in your hands? If that stuff gets between your tire and the pavement mid-corner you'll have some serious traction issues. Even if you keep it together and stay out of the weeds your traction will be reduced for a while, the tires kind of soak it up. It's bad news to get coolant on a race surface.

A basic overview of coolant and pressure in an automotive cooling system.
http://auto.howstuffworks.com/cooling-system3.htm

 

[JeremyCT]

Would it be possible, or advisable, to run the stuff computer overclockers use in their cooling loops in automotive cooling applications? What I'd really like is something that can stop radiators from rusting out.

Flush and change your coolant every 2 years like you're supposed to.

There's only so much anti-corrosive and pH buffering agent agent stuff that can be added to coolant. It gets used up over time and eventually the coolant needs to be exchanged.

 

[JeremyCT]

I didn't see that we had a page 2 until after I'd posted ...

Copper Sulfate is a biocide but honestly its super mild. Its sufficient for your cooling loop and the worst thing that's going to happen if you spill it on yourself is mild skin irritation, and it needs to be pretty strong mixture for that to happen.

It's important to realize that copper sulfate reacts pretty strongly with iron though. Oxides it like crazy. Since people are bringing up automotive applications and how it might translate to that realm, that's good to remember.

There are reasons we use what we use in PC cooling systems and automotive systems, and also reasons why they're not entirely interchangeable. Some stuff does work in both. I use an automotive surfactant/water wetter product in my PC loop because I like the pH buffers and anti-corrosives it has in it, plus the surfactant aspect makes bubbles easier to bleed. I run plain green 50/50 coolant in my vehicles though. Well, ok, the BMW used to get special stuff (Zerex G-05), but that was only because I liked it more.

 

[ssjwizard]

I didn't see that we had a page 2 until after I'd posted ...



It's important to realize that copper sulfate reacts pretty strongly with iron though. Oxides it like crazy. Since people are bringing up automotive applications and how it might translate to that realm, that's good to remember.

There are reasons we use what we use in PC cooling systems and automotive systems, and also reasons why they're not entirely interchangeable. Some stuff does work in both. I use an automotive surfactant/water wetter product in my PC loop because I like the pH buffers and anti-corrosives it has in it, plus the surfactant aspect makes bubbles easier to bleed. I run plain green 50/50 coolant in my vehicles though. Well, ok, the BMW used to get special stuff (Zerex G-05), but that was only because I liked it more.

I was not suggesting CuSf for automotive purposes. I was saying H2O + CuSf or H20 + Ag for PC is ideal and has sufficient anti microbial properties while being relatively mild on humans and drains.

 

[JeremyCT]

I know, I was pointing that out for the benefit of magellan and ATMINSIDE.