Question - what does 0C (32F) mean to automobiles

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Yep, that's the freezing point of water, which is now an obsolete coolant, not having been specified for decades that I'm aware of.

But what line in the sand does 0C actually define for automobiles ?

"below freezing" is mentioned as a point in which "things" change in their behaviour, but what's the change ?
 
Not much, in my view. I run washer fluid year round that won't freeze until -45 C, and I certainly don't use water as a coolant, as you point out. The only change I ever notice when approaching the freezing point is frost on the glass on occasion, which wouldn't be there otherwise. The humidity is often low enough here, too for the frost to not show up anyhow.
 
It means that there is more resistance to flow of fluids such as oil versus when it is warm or hot.. Also, that you get to know how well your heat works, if it works at all.

Your car generally doesn't care if it's in Antarctica or if it's in the tropics or hottest regions of the planet. As long as it has gas or diesel and proper fluids it should be happy. General physics apply.
 
It means that if you wash your car on the way home from work at the car wash you might not be able to open your doors in the morning.
 
It was +42C (108F) here yesterday, it means I can touch the steering wheel without wincing in pain, and a vinyl seat isn't going to melt flesh from my bare legs (also cold enough to wear long pants).
 
Originally Posted By: Shannow
But what line in the sand does 0C actually define for automobiles ?

Slippery/icy driving conditions?
 
For people that live in places that the temps hardly ever get to the freezing point, it means they have to warm up their cars for 30 minutes, to get the "fluids flowing" and take extra 30 minute drive from work to burn off water and fuel dilution.

For people that live up north it means nothing, maybe keep an ice scraper in the car just in case we have freezing rain.
 
Any plastic or rubber part will be stiffer....to the point of "crossing a line"?....it would vary.
A useable example of a "line" could be the one presented by lubricants which stiffen and let bad U-joints, suspension bushings and sway bar links creak.
Kinda useful really.
 
Nothing. 0F is when cars start to moan and groan, cranking times are longer, power steering takes a moment to get going, etc.
 
Originally Posted By: Ethan1
Nothing. 0F is when cars start to moan and groan, cranking times are longer, power steering takes a moment to get going, etc.


Yep.
0C is fairly comfortable while 0F is starting to get really cold.
 
Bingo!

It's a temperature chosen to measure attributes and behaviors of materials and systems used by the vehicle. The changes in behavior are occurring as temperatures drop (or rise).

In the case of oil, IIRC, multi viscosity oils are measured at 0c and 100c.

Originally Posted By: Warstud
I think it's used as a reference point that people can relate to.
 
It means Nothing.

10*F-15*F is when I notice changes,

cranking is a little slower, High idle stays much longer, etc.

32*F is any other day for me.
 
Water isn't an obsolete coolant it is just mixed with coolant. As you all know to me below 60*f as far as I am concerned may as well be freezing.
 
Thermodynamics question. Energy is transferred away from the vehicle. Chemical reactions slow down in cold. Oil thickens (cold start) and it takes longer for your engine to get to operating temperature. Cold air is thicker more dense than warm air. Tire pressure tends to decrease. Batteries drain faster in cold. In my experience, excessive heat 37.7 C > not good. Especially, driving 4x4 slowly in Utah or the desert in summer. Excessive heat not good for engines.





Respectfully,

Pajero!
 
Originally Posted By: Pajero
Thermodynamics question. Energy is transferred away from the vehicle. Chemical reactions slow down in cold. Oil thickens (cold start) and it takes longer for your engine to get to operating temperature. Cold air is thicker more dense than warm air. Tire pressure tends to decrease.

Yes, but the things you mention happen any time a temperature drops, be it from 30C to 20C, or from 20C to 10C, etc.

OP asked for the relevance of 0C point specifically.
 
Originally Posted By: HoosierJeeper
x2. 32 degrees means it's car wash weather!

x3! 34° right now and I just came in from washing the Carrera!
 
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