Pure antifreeze hypothesis

[mjoekingz28]

Anyone care to guess what pure dexcool will show for freeze point?


I read awhile back that straight antifreeze froze at zero degrees Fahrenheit. So, would my Prestone gauge/monitor be able to accuratey gauge it?


Would temp do you think the gauge will display as the freezing point/boilover for concentrate?


I think it will be off the charts sinc I think it is thicker that plain water and will thus give false readings....kind of like tricking the censor-bot.

 

[horse123]

If pure antifreeze had a freezing point of 0º, how would half water antifreeze not freeze in winter in most of the united states?

 

[Falken]

Coolant needs water, there is no recommended application that calls for straight Coolant that I am aware of.

Measuring the effectiveness of a component to project its capability without being combined with water would be difficult with the tools that are designed to measure coolant with water added.

Note, an engine block will freeze with straight coolant BEFORE coolant that is correctly mixed with water.

 

[kschachn]

A little chemistry (or physics) goes a long ways.

As long as the coolant is ethylene glycol based then the chart should be accurate. Also note that the freezing point depression of water is independent of the solute on a molar basis until you pass the 50% mark.

 

[kschachn]

Originally Posted By: Falken
Note, an engine block will freeze with straight coolant BEFORE coolant that is correctly mixed with water.


Correct.

 

[eljefino]

As it was explained to me and poorly relayed in retelling, Confusion in molecules lowers its freezing point. Throw some salt in water, it's enough different stuff in there it keeps bonds from forming.

Pure antifreeze has nothing else in there, so it crystallizes. Water interferes.

There are some antifreezes out there like RV antifreeze that turn to slush. It doesn't flow, but it doesn't expand like ice, so it doesn't bust stuff.

 

[Cardenio327]

Originally Posted By: kschachn
A little chemistry (or physics) goes a long ways.

As long as the coolant is ethylene glycol based then the chart should be accurate. Also note that the freezing point depression of water is independent of the solute on a molar basis until you pass the 50% mark.

Great chart. I have heard that pure antifreeze gels at higher temperatures than it freezes when properly mixed with water.

To answer part of the OP's question: Yes, you can use your Prestone tester because Dexcool is ethylene glycol based, just like most [or all] of Prestone's product line.

Your Prestone tester probably cannot be used with propylene glycol based coolants such as Engine Ice and Sierra.

Another reason to not use pure antifreeze: It is combustible when not properly diluted with water, if it happens to spray on the exhaust manifold it can cause a fire.

 

[kschachn]

Originally Posted By: Cardenio327
Great chart. I have heard that pure antifreeze gels at higher temperatures than it freezes when properly mixed with water.

Another reason to not use pure antifreeze: It is combustible when not properly diluted with water, if it happens to spray on the exhaust manifold it can cause a fire.


Pure ethylene glycol is a poorer working fluid than water for cooling systems since its specific heat capacity is lower. It can't carry away heat as fast as water (or a water/glycol mixture), so you always want to follow the manufacturer's recommendation on concentration levels. Usually a min/max is clearly specified on the bottle for concentrates.

On the other hand it is relatively cheap, non-corrosive, miscible with water and has a low vapor pressure. Plus a distinctive smell that can alert you to a leak.

 

[cronk]

When I was in high school, I worked at the local Kmart.
There was a pallet of coolant in an unheated stock room that froze during a cold week of winter, and several of the gallon jugs burst open and made quite a mess.
Most coolants should be mixed no stronger than 70% coolant.

 

[mjoekingz28]

It read off the chart, aka cold like Antarctica.


So I guess that says antifreeze is more viscous, heavier, thicker, denser than water AND the gauge (floating pointer) goes by viscosity.

 

[Brons2]

There is no such thing as "Pure Antifreeze". Antifreeze has additives.

What we should be talking about is pure Ethylene Glycol.

 

[kschachn]

Originally Posted By: mjoekingz28
It read off the chart, aka cold like Antarctica.

So I guess that says antifreeze is more viscous, heavier, thicker, denser than water AND the gauge (floating pointer) goes by viscosity.


No, that type like the ones that have floating balls rely on specific gravity, not viscosity. They are essentially a cheap hydrometer that is uncompensated for temperature.

Here is a chart of specific gravity for ethylene glycol/water mixtures at various temperatures. The type of tester you have will be outside its range for 100% antifreeze. If you want to test what you have you need a refractometer.

 

[kschachn]

Originally Posted By: Brons2
There is no such thing as "Pure Antifreeze". Antifreeze has additives.

What we should be talking about is pure Ethylene Glycol.


Do you have anything that shows the additives to antifreeze would alter the freezing point? I've only seen things added such as lubricants or corrosion inhibitors.

I don't know how it could unless it was a significant fraction of the overall volume. Like I mentioned, freezing point depression is independent of the solute so you need a lot of it to make a difference. There aren't any "super" depressants.

 

[kschachn]

Originally Posted By: mjoekingz28
It read off the chart, aka cold like Antarctica.


In this case "off the chart" really only means off the chart - not like Antarctica. Look at the graph I posted and you will see that 100% ethylene glycol freezes at about 10 degrees F.

 

[Garak]

Originally Posted By: Brons2
There is no such thing as "Pure Antifreeze". Antifreeze has additives.

True, but you will still get a graph something like was already posted. Experimental verification of that, using off the shelf antifreeze, is a common undergrad chemistry lab assignment.

 

[Shannow]

Originally Posted By: mjoekingz28
It read off the chart, aka cold like Antarctica.


So I guess that says antifreeze is more viscous, heavier, thicker, denser than water AND the gauge (floating pointer) goes by viscosity.


DENSITY...

 

[Shannow]

Originally Posted By: horse123
If pure antifreeze had a freezing point of 0º, how would half water antifreeze not freeze in winter in most of the united states?


The salt in your larder is a solid at room temperature, and significantly above that temperature...put some in the frypan and try to melt it.

Water freezes at 32F

Mix them, and they freeze together much lower than 32F...throw solid salt on ice and it melts.

Intuition means nothing unless it's tuned.