Rick says propylene glycol, but he lives in some English-speaking island country somewhere in the North Atlantic, and propylene glycol might actually be main ingredient in their antifreeze, since they often do things differently there.

What I'm saying is: ethylene glycol, propylene glycol, even glycerol, these will all work, mixed with water, as antifreeze.

The recipe may also include some corrosion inhibitors, and also as you have mentioned, dye.

I have no idea what the dye is for. Maybe just to make it look unnatural, just so people won't confuse it with water, or something good to drink.

BTW, it has a sweet taste, but whatever it is made out of, you probably don't want to drink more than just a taste.

Also, for all the virtual tourists reading this post, I thought I'd add a closeup picture of a label from a bottle of antifreeze purchased from a big-box retailer the FUS. As you can see from the warning blurb, this product contains: ethylene glycol, diethylene glycol, sodium 2-ethylhexanoate, and sodium neodecanoate.

The warning label just tells you that these "dangerous" ingredients are part of the recipe, and this list likely exists to satisfy some mysterious legal requirement. Any "harmless" ingredients not required to be mentioned here, are of course, not mentioned. I am guessing the dye is one of these harmless ingredients.