washer fluid makes no sense

[y_p_w]

Originally Posted By: dlundblad
Windchill has no effect on liquid?

Windchill is only about perception on bare skin. Wind might actually cause a slight amount of actual temperature reduction, but nowhere near what a windchill factor would indicate.

For a liquid to freeze up would require mostly actual temperatures dip below a certain point. An inanimate liquid can't "feel" anything. I think air pressure might have a small effect.

 

[edhackett]

Originally Posted By: dlundblad
Windchill has no effect on liquid?


Windchill, no, as that is purely human perception.

Wind, yes, due to increased evaporative cooling.

It takes energy to convert a liquid to vapor. Heat is carried away from the liquid by the vapor. Exactly how much depends on the liquid, the temperature, and the atmospheric pressure. At its boiling point water takes 40.68 kJ of energy to convert 1 L of liquid to vapor. That's 2161 Btu or 0.633 kW/h. The latter being the equivalent heat output of a 1500W space heater over 25 minutes.

Methanol has a heat of vaporization of about 35 kJ/L and Isopropyl alcohol 44 kJ/L. The heat of vaporization increases as temperature decreases.

This is the main reason washer fluid above it's freezing point can freeze on your windshield. Evaporation carries heat from the liquid washer fluid, dropping its temperature below its freezing point.

Ed

 

[Greggy_D]

Originally Posted By: dailydriver


The yellow Prestone stuff used to say -34*F on the label, but that changed about two years ago to -27*F.

I noticed that also. They cheapened out on their product.

 

[dparm]

Originally Posted By: Greggy_D
Originally Posted By: dailydriver


The yellow Prestone stuff used to say -34*F on the label, but that changed about two years ago to -27*F.

I noticed that also. They cheapened out on their product.



Nothing a little rubbing alcohol won't fix.

 

[TiredTrucker]

Originally Posted By: AandPDan
I've never had a problem with the Prestone Deicer.

Think "wind chill" on your freeze up.


The Prestone stuff is what I have come to rely on. The blue stuff just freezes up the spray nozzles on my semi truck. I can't afford not being able to see properly herding 80,000 lb of truck down the road. The Prestone Deicer stuff is the cat's meow.

 

[BMWTurboDzl]

I use BMW-branded fluid. They have a summer and winter formula. I've had the winter freeze on my windshield but it works very well for de-icing.

 

[SOHCman]

I added 91% iso. Alcohol to rainex orange thas is good to -20 but still seems to freeze at the nozzle for some reason. The alcohol seems to lower the freeze point proportionately.

 

[Doog]

Originally Posted By: nitehawk55
I use Rain-X and also use the summer and winter versions of the washer fluid they sell .

The winter stuff is good to -40


I was in Florida last week and out of washer fluid. Stopped at an AAP and told the guy I needed the -20F stuff. He had the orange Rain-X stuff that is good to -25F. Much better cleaning with the Rain-X and no streaking.