I am still shocked that it can be pondered whether antifreeze helps the engine warm itself up.

FYI
 

Antifreeze - Wikipedia, the free encyclopedia
http://en.wikipedia.org/wiki/Antifreeze





.

@JEBalles,
I disagree. Not to get into an argument but you may want to look that one up.
I am a Power Engineer specializing in water treatment.

Nope.

Surfactant = surface active agent; any compound that has greater activity at the surface, whether "impurity" or "intentional".

The test is simple. Take a sample of water. Put it in a sealed bottle. Shake it. Do you see any bubbles/foam that persists once you stop agitating?

If so a surfactant is present.

I ain't calling anybody out here, but I don't understand how distilled water could have no surface tension. You saying a water skipper would drown in it?

I use bottled distilled water in my espresso pot, so just to see, I poured some into a clean glass and put a staple in. It floats on the surface tension just fine. I poke it with a fork, it sinks to the bottom.

So ... what gives?

Gosh who would or did say that?

The prior remark was that contaminants could not influence surface tension. That is incorrect; they may or may not, depending on whether they are present at the interface in sufficient quantity and if the balance of inter- to intra- molecular forces is altered.

The original question, as I heard it, was:

Given two identical cars, one filled with water, one with a 50-50 antifreeze, which warms up quickest.

I replied the mixture has a lower heat-carrying capacity. Someone else replied that the efficiency of the heat transfer will probably be improved because of additives. I'm comfortable with both comments.

Someone else said the comment about contaminants and surface tension. I did not agree with that comment.

Anyway --> Use a good 50-50 mixture and take good care of your car seems to be something we can all agree on!