Originally Posted by Rzeppa
I did considerable research on this topic when I was offered some unused, but old ethylene glycol. It turns out that the "corrosion inhibitors" that they add to automotive coolant are simply buffers to react with any acid found inside the cooling system. Eventually they are used up and the coolant becomes acidic and will start to corrode the surfaces inside your cooling system. The "test strips" are simply litmus paper.
basically, yes, there are 3 way and 4way test strips that molybdate, nitrate, freezepoint and i can't remember the fourth thing (we only carry the 3way test strips here).