I've never tried it, but I think for the most part you'll find that many of us on the forum don't buy or believe in the 'snake oil sales' many of the additives claim. Here'* some proof for making that statement Redline WaterWetter® Review | The Truth About Cars

I've only heard good things about Water Wetter, a friend of mine with a Blown '55 chevy runs it and he says it works.

Don't see how it can drop 20* The thermostat controls that.

The guy I was talking about '55 has the center knocked out of his thermostat to keep water flowing but to restrict it enough that the radiator can still cool it.He don't drive it much on the street anymore mainly the strip.Drag Strips don't like anti-freeze spills on the track, hard to really clean up.