[TR] Interesting data on coolant

[McGaheyRx at aol.com]

Not to split hairs, but there is some down right misleading stuff in the  
explanation below.
 
When you mix antifreeze with water, you create a solution with an  elevated 
boiling point. It is misleading to say that water still boils at 212f  
because you are now dealing with a solution with an elevated boiling  point.
 
The glycol does NOT separate from water - it stays in solution - if the  
solution starts to boil, the steam that evaporates first will be H2O, but  its 
misleading to call that a separation of glycol from water - the part that  
doesn't boil away remains a water/glycol solution - with an elevated boiling 
 point - which will be elevated even further under pressure.
 
Boiling point elevation and freezing point depression are basic physical  
principles with other applications - its the same principle used when salt is 
 applied to road surfaces to depress the freezing point of H2O on the road  
surface. 
Its just silly to say that water still boils at 212f when mixed with  
antifreeze in your radiator - its not pure water anymore, its an aqueous  
solution with an elevated boiling point.   
 
Cheers,
Jack Mc 
(i knew that major in chemistry would come in handy someday)
 
 
 
 
 
In a message dated 3/2/2014 1:33:19 P.M. Eastern Standard Time,  
spook01 at comcast.net writes:

I was  speaking with a cooling systems engineer the other day, and he was 
telling me  some interesting facts on how coolant acts within an automotive 
cooling  system, and how systems are designed.
When coolant is mixed 50/50 with  water, the water stills boils at 212f at 
sea level.  The glycol portion  doesn't boil at that temp, but separates 
from the water.  Hence, any  steam in the system is 100% water, not boiling 
glycol.  Boilover, that is  the gush of coolant out of the radiator of a hot 
car, is caused by this  steam.
This steam, while the engine is running, can cause an insulating  pressure 
barrier within parts of the engine allowing the metal to over temp in  
spots, causing pre ignition, damage and loss of power.
The hot cooling  fluid reaches the water pump, where pressure changes due 
to pump action take  place.  A steam bubble can form on the intake side, 
restricting coolant  flow through the system.  I was told 2-2500 rpm is 
generally the entry  point for this to happen.
If 100% coolant is used, the boiling point is  raised overall to the 
boiling point of glycol but freeze protection is  less.
Obviously, the boiling point of water rises with pressure, hence our  
pressure caps.  And, that's why unpressurized systems aren't used with a  50/50 
mixture.
100% coolant of various types have their strengths and  weaknesses.  Most 
are designed to work mixed 50/50 because the mixture  "clings" better to the 
metal walls of the block/head(s) allowing better heat  transfer.
The main feature of using normal coolant mixtures is this surface  tension 
relaxation and drop in freezing point.
The first point can be  proven by heating a container of 59/50 coolant 
mixture to 212f or so, and  collecting the steam on cool metal.  It's water!
This guy said that  the normal mix is used for corrosion control, slight 
improvement in cooling  efficiency, and, mostly, for freeze protection.  He 
talked about about  additive packages being different for different types of 
coolants (long life,  etc.) and how some can interact.

I also asked him about waterless  coolant, and he said it was too expensive 
for use in mass produced autos, but  did offer significant advantages in 
boiling point and going pressureless in  systems which equates to longer hose 
and pump life.
Interesting,  eh?

Sent from my Verizon Wireless Phone

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