Straight water, or antifreeze?

[Power Wagon]

Which cools better, straight water, or water and antifreeze mix?



I've heard arguments for both. One, straight water cools better because water absorbs more heat per gallon to raise it's temperature one degree than does a mix.



Argument two, since anti-freeze doesn't boil nearly as easy, the mixture cools better, since you can have a higher water temperature raise going through the engine and not boil. Since cooling is a function of temperature differential between the radiator's flowing water and flowing air, the hotter the liquid entering the radiator, the more heat it loses, since hte differential between the water and air is greater.





Well, ok, now that i've made a simple question complex... . Any takers?



Mark

 

[Alan Reagan]

"I've heard arguments for both. One, straight water cools better because water absorbs more heat per gallon to raise it's temperature one degree than does a mix. "



The mix cools more effectively because the anti-freeze also has an anti boil component that raises the boiling point of the coolant thus making it more effective/efficient across a wider temp range.





"Argument two, since anti-freeze doesn't boil nearly as easy, the mixture cools better, since you can have a higher water temperature raise going through the engine and not boil. Since cooling is a function of temperature differential between the radiator's flowing water and flowing air, the hotter the liquid entering the radiator, the more heat it loses, since hte differential between the water and air is greater. "



Go back to argument 1 and add it to argument 2 and you have your answer. Water does absorb and transfer heat better. That's why you don't use straight anti-freeze. What you want is to modify the desirable characteristics of water for heat removal so that problems are eliminated in the broadest possible temperature extremes that will have to be endured by the engine. The anti freeze alters the characteristic of water to freeze at 32F or boil at 212F. Besides performing the corrosion inhibition the only job of the AF is to widen the acceptable operating parameters of the water. Straight antifreeze is not as effective in cooling as water. The preferred mixture is 50/50 but never more than 67/33 (W/AF) or less 33/67 (W/AF). Outside those ranges the mixture is fairly ineffective as a protector/coolant(with anit boil properties)/antifreeze.

 

[Doc Tinker]

Antifreeze raises the boiling point of the water that gets mixed with it. Therefore an engine can run at higher temperatures without boiling over.



Water cools faster when heated and left standing. I've felt antifreeze/water mix retaining heat for many hours after it's been heated.



For the ultimate in heat dissipation, use alcohol.



Doc

 

[The patriot]

Water transfers heat better. Might want to drain your heater core. If you use the a/c, you could freeze it.

The water in a pressurised system (assuming it to be 15 PSI) will boil at approx. 250 deg.

I dont know what the radiator cap is set at on our trucks. Probibally around 15 psi. ?

Eric

 

[DennyDay]

Antifreeze

In days past, before engine operating temps had to be increase for cleaner burn, nobody used antifreeze in the summer, just straight water. Even most antifreeze was wood alcohol based, and would boil well below 212 deg. F.

Denny

 

[EMDDIESEL]

When we used to go Drag racing, we used to run straight water with Red Line "Water wetter" which increases cooling considerably. Summit carries it. I have no plans to use it in my Ram since even on te hottest days in traffic, my truck never runs hot.

If i had to choose between straight water or Antifreeze mix, i would say straight water would give you better cooling results.

On all but the newest diesel locomotives, they have straight water with an anti corrision inhibitor. But its mainly a cost issue