On Sun, 20 Feb 2011 03:08:26 -0800 (PST), harry
wrote:

On Feb 19, 7:26*pm, Smitty Two wrote:
In article
,

*harry wrote:

I didn't know anyone changed anti-freeze anymore. I just top mine up
with neat anti-freeze & then I'm sure it's not too weak.

Well, that's a spectacularly bad idea. Anti-freeze makes a ****ty
coolant. It's there to keep the real coolant - water - from freezing.

Some aircraft run on neat antifreeze. In very cold climates neat
antifreeze is recommended.

Wikip:
"Pure ethylene glycol freezes at about -12°C (10.4°F), but when mixed
with water molecules, neither can readily form a solid crystal
structure, and therefore the freezing point of the mixture is
depressed significantly. The minimum freezing point is observed when
the ethylene glycol percent in water is about 70%, as shown below.
This is the reason pure ethylene glycol is not used as an
antifreeze—water is a necessary component as well."

The reason I top it up is that the
antifreeze evaporates leaving water behind if there's a leak or the
sytem overpressures.

"the increase in boiling temperature is due to pure ethylene glycol
having a much higher boiling point and lower vapor pressure than pure
water; " This is one reason ethylene glycol evaporates
less than water. The antifreeze that evaporates more is alcohol.
Does anyone still use that?