Agreed, it has the potential to be a good product but in the real world it doesn't seem to turn out that way. The corrosion inhibiting compunds in DexCool are less abrasive than what is used in the green stuff so in theory it should lead to longer water pump life but once the level drops a bit and air gets in the system, forget it. That's when the sludge forms and the engine cooks. I imagine a properly maintained system using DexCool would be fine, but most of us on this forum are driving someone else's neglected junk.

I found an interesting piece in a web search that was a bit too pro DexCool but it did include a cool tip regarding the use of a multimeter to check coolant quality. Has anyone seen this before?All About Dex-Cool® - GETAHELMET.COM

 

There are simple turbidity, refractometer and simple conductance meters made just for this that will give you general "condition" reading. They basically are just measuring too much/too little coolant to water or too much salt/ions in the solution.

As the major concern/problem of the coolant is the chemical salts forming from bad water, contamination, electrolytic reaction, etc. You can use a multimeter to test the conductance of the solution but unless you have a specific gap setup or the correct probe it can be kind of an un-exact science. Fresh DI water and pure antifreeze will have a conductance of theoretically zero but the additives in most of the antifreeze will increase this and if your water isn't DI it will have a high conductance.

On my 2005 Range Rover they used the (re-labeled) and double priced up BMW Blue Coolant that worked well until they switched it with DexCool after almost the first service and it caused a lot of corrosion. They also skimped a bit on the mixture and type of water as the pressure blew out the cheap BMW reservoir and several hoses very quickly.