So, you have tested DOT 4 or know someone who has? If not, then this particular question has likely not been answered over the last two decades. Seems the "silliness" part comes in when the robots take over and experimentation is deemed unacceptable.
You...are so far off base on this insanity that after reading pages upon pages of this I'm bound to think that you don't fundamentally understand thermodynamics. Let me go over the 10,000' view...so you can understand.
1) Heat is a thing that is actually random kinetic energy in molecules. It transfers in one of three ways. Radiation, conduction, and convection.
2) The fan blowing air over your radiator or fin stack is using both convection and conduction...but primarily is modelled as conduction.
3) Why not model convection and radiation? Well, the simple answer is that they're mathematical rounding errors of influence.
4) Why use brake fluid as coolant? Um...no. If you understand anything you'd immediately look at this and know why.
5) Why do the rest of us have this immediate response? Thermal capacity. The energy it takes to make a substance go up in temperature.
6) Why does this matter? The delta in temperature represents a heat flow. Since input temperature is fixed (CPU), and output temperature is fixed (environment), the larger the heat capacity the more you can reject to the environment.
7) What about cavitation, and superheated gas bubbles? I would posit that you don't understand physics....because that 114 C temperature is then distributed to an IHS, a block, and then is transferred into a moving fluid. To be clear, the fouling layer is more of a practical problem than your magical superheated gas bubbles from boiling water. Note that isn't just me making things up.
8) But, why am I not just making things up? Well, the heat of vaporization for water is magnitudes of order higher than the thermal capacity. To get any significant boiling you'd need a huge concentration of heat or high heat. The problem with both is you'd basically be breaking your CPU down to get that...so it's not possible. So...water is not viscous, resists boiling, and has a large heat capacity...
9) But, why water? Well, let me go back to some basics. If you look at a water molecule it's actually pretty polarized...so the energy required to get it to vibrate more is pretty high....much higher than hydrocarbons. What is brake fluid again? Oh yeah. They do make up for this by being heavier and requiring more energy...but that generally also makes them resist flow and thus be more viscous.
10) Now let me address heat pipes....because people think they're magic. If you create a low pressure environment you get water's boiling point to drop. Same huge thermal capacity, and enormous vaporization energy, but at a temperature below the atmospheric boiling point.
11) If you then create a tube, where one end is at a heat source and the other is surrounded by ambient air it's easy to get the water to phase change back, dumping that huge energy load into the ambient environment.
12) Since it's a tube you're generating a fluid (water vapor, then liquid water) flow loop. You now have a phase change cooler that takes advantage of a low partial pressure water to depress the boiling point, and thus phase transition, into a workable temperature for the CPU to generate, and have cooled with the ambient environment, with minimal losses during relocation of the fluid given minimized surface contact and thus low conduction. You then have good conduction via an ambient fluid (air) flow over a huge surface area (fins).
Now....all of the above is to say this. When I started building computers most coolers were solid. Think the Intel stock coolers, with a metal puck and aluminum fins. Not great, because the heat had to travel along a large distance. This meant CPU hot, fin edges cool, and everything between was a gradient. The automotive industry knew this would not work for them, because they had explosions in one area and thus needed to dump energy and have it moved away faster than it could diffuse. They thus designed liquid cooling...which to this day uses water because of a high heat capacity...though adding stuff to it for not heat transfer reasons.
Back to computers, when the manufacturing tech to make heat pipes went from the niche to the common/affordable it spelled a new age. First we got less mass, then we got hotter CPUs, then we got more heatpipes and mass to compensate for hot CPUs, now we've got internal throttling to manage the insane heat loads chips generate...because even high end coolers can sometimes be stalled out by enormous peak loads. It's been a long way getting here...but as most users find a 7600x (or 5600x) more viable than a 7900x, the need for water cooling is capped as a very expensive toy...out of reach or need for most people.
Seriously though, brake fluid? The stuff is insanely hygroscopic, it's designed to transfer energy from a pump cylinder to a brake, and resist things like cavitation due to boiling because its boiling point is 205+ C when dry. The problem is that hygroscopic part...and this is largely why it's not suitable. For comparison's sake, you know a car gets hot. You know that the fittings for a brake line are meant to be very resistant to infiltration, and thus are very unlikely to allow water vapor in any form to enter. Your average CPU cooling loop is designed to be relatively speaking not that. It's designed to be filled, have some losses, and because of design allow as much fluid to move as freely as possible. You may well see a performance increase initially...as the thermal capacity of glycol and the like is huge...but they are equally viscous and prone to degradation
Glycol properties It's trading a fluid that is easy to work with, and cheap, for something that would require constant maintenance and an even more custom loop. I...think you've found the gold plated platinum cored claw hammer solution to a problem that already has a perfectly viable hammer.
I'd also posit that "because nobody tried it" is not a real argument. I once knew a guy who filled his custom loop with cheap vodka, because the ethanol was technically better at conducting....and he had a reason to keep a bottle around "for the computer." Ate every seal in the computer, and he had no issues replacing it because. Just because somebody tried it doesn't mean it's good or bad. I'll stick with keeping brake fluid out of my house....I've seen what it does to paint and plastics....though you're welcome to discover whether that rubber is something that is good for the fluid or not.
