That's my background Odgie , 15 years in the car radiator trade ,and antifreeze definitely drops running temperature , even conducted tests with hand held laser thermometer to back up incar gauge.It makes at least 5C and up to 10c difference over plain water.
I bow to your better experience Kev, all the research I did at the time (it's a few years ago now) reckoned pure water was best (something to do with heat transfer to molecules), but to be honest most of it was hearsay rather than empirical testing. Perhaps it's just folklore from earlier times when anti-freeze wasn't as good? Anyway, I'm happy to stand corrected (learn somethin new every day eh? ). Cheers.