You know it's REAL cold when...

[Peakster]

Originally Posted by RH77

Just polling, what is the most common reason for the failure of vehicles to start in extreme cold? Fuel-line freeze up, coolant frozen-up, battery shot, etc?

I would think that the fuel vapors would simply not want to ignite in extreme cold. I remember one deep-freeze, my Escort wagon wouldn't start until I figured out that if I turned it over for about 20-30 seconds straight, the engine would (weakly) sputter to life.

The Geo often does the same thing, except that it hasn't taken more than about 5 seconds of cranking.

[metroschultz]

I lived in northernWest Germany in the 80's. Every car I knew had a block heater in it. You oil would freeze in the case if you didn't keep it plugged in. In the military we kept the vehicles running when overnight predicted temps were > -40f. One Feb. our high for the day got all the way to -15f. BRRRRRRRRR. F...in Brrrrrrrrrr.
On this side of the water the worst thing that I ever ran into was my own stupidity.

I took a trip north to visit my Mom (in the Poconos). Feb. 1989. In Rich. Va. temps were ~ 40f.
I drove a 1974 Mercury Capri, (Germ. Import, 2.0L4, 5spd, ran great, got killed by a Buick, man I miss that car. ). Some Dumass didn't put antifreeze in the cooling system. Hi my name is Dumass.
Moms overnight temps were in the -10f range.
Car wouldn't start, engine was locked up.
Who woulda thought?
Dad had a torpedo style kerosene heater, we aimed it at the front of the car and let it do it's job.
An hour later the car started and seemed to suffer no Ill effects.
That little car got incredible mileage for what it was.
It always ran, unless it was frozen.
I miss that car.
S.

[TomO]

Originally Posted by RH77

Just polling, what is the most common reason for the failure of vehicles to start in extreme cold? Fuel-line freeze up, coolant frozen-up, battery shot, etc?

RH77

I would say that around MN that a frozen/weak battery is the most common cause for a no start condition.

But given that all things are equal and all parts of the motor are new and fine. We know that combustion needs three things: Air, Fuel, and spark. And we also know that fire needs three things to occur: Air, fuel, and enough heat to ignite.

I hypothesize that when temp are, say, -40°F that the fuel has a hard time atomizing well. That would lead to a non ideal Fuel/Air ratio. Also the fact that the air coming into the combustion chamber would be a chilly -40°F would contribute to poor ignition of the fuel/air mixture. This may explain why some vehicles require a few seconds of cranking time as this will warm up the combustion chamber somewhat due to friction from the piston and the spark from the spark plug.

Now when you throw a weak battery on top of all that jazz, you can see how most cars would be unable to crank any longer after the initial warm up and become stranded or require a jump start.

So there you have it...my two cents on the matter of what happens when it's really cold, lol. And knowing is half that battle.

[MetroMPG]

I was told by some people with classic cars that in the early days, there was no antifreeze. If you owned a car and wanted to use it in the winter (many didn't - no plows either), you drained the water from the cooling system after using the car and refilled it for your next drive.

From articles I've seen, the CAA says battery failure is the most common call from its members in winter weather.