Y’all are giving great tips on what to do and how to do it, but still I say, “Why?”
Unless we are dealing with Antarctica-type temps, what difference does it make, in terms of what is going on inside of your car?
Your engine is at its most unprotected when you first start it. After that, if it runs, it’s protected. Isn’t it?
“In much wisdom is much grief; and he that increaseth knowledge increaseth sorrow.” - Ecclesiastes 1:18
In Charleston it wouldn’t get cold too often, but when it did come to hard frost, it was mean. I had to park outside and it was humid out, so my car would be completely frosted over. So I would start my car up, shut the door, turn the warm heat on, and start scraping it off. By the time I got around to the front, the air would have melted a few small holes in the ice, and by the time I was done the car would be warm and I could defreeze my fingers.
I didn’t do it for oil or anything else, it was because I was a pussy about the cold.
I sold my soul to Satan for a dollar. I got it in the mail.
George, I bought one of those small heaters for the farm truck and they don’t work worth a crap. You’re better off buying a small power inverter to run your heat lamp while driving, though that doesn’t sound very handy.
Milossarian:
No much. Its an accumulative thing. It helps keep the engine tight, compression high and part of the other preventative maintenance you do to your car. A tight engine will have high compression and get better miles per gallon. Keeping the rings in good condition minimizes blow by, loss of compression and prohibit vapors into the oil which degrades the quality of your oil.
Bringing up the engine to temp quickly from extreme cold streses the metal eventually contributing to fatigue. Depending on the parts they may heat up at different rates weakening joints and gaskets which over time will be noticed.
If your not keeping your auto for the long haul then it won’t make much difference to you during your ownership. Resale value is mostly done on the basis of looks. Few people get a compression test done as part of a used car purchase.
If you’re in for a serious attempt to make your car last for a very long time at minimal cost then you have to do the maintenance.
I’d be the first to agree that a small power inverter (~150 watts, maybe $20-$40) would be preferable, if only because having an actual electric socket makes it so much more useful. I guess personal experience with them will vary with the version you have.
I’ve only used mine on those rare occasions when I had to get moving right away and didn’t want to be hassled by windshield frost; I wouldn’t want my life to depend on the amount of heat one of these things puts out, but it worked satisfactorily.
"You’ll never get as much out of being right as you will from finding out why you were wrong . . . " The Papoon Principles Ch. 1.
As for ice, Im in calif, nice sunny Calif, some rain but I see people on the news with all this ice they have to take off every day.
The question is, why don’t they put on a car cover at night?
Handy, I live in Winnipeg, mighty chilly here. I don’t use a car cover for a few reasons (these are just mine)
Occasional ice storms, freezing rain would make it mighty hard to get off.
Periodic huge snowfalls: see answer one
Who wants to spend more time outside in a 2400 windchill than absolutely neccessary?
That’s about it. I have a new car, but I still let it run for a while because I friggin hate freezing in my car.
Writing from NJ, where we start wimping out in the 30F range… Am I to understand that this warming up stuff is only for truly frigid temps, and when it is up in the 20F vicinity there’s no need for a warmup?
My car, an 88 Corsica, will run without stalling as son as I start it. It did this last week, when it was about 11 degrees below zero (F). It certainly got up over 15mph in less than 10 minutes.
Should I do tis? Depends on the day, sometimes. I have had to pull over while it defrosted. Usually, when it’s quite coled, we get frost, so I warm it up for the time it takes to scrape frost.
One reason “they” say to warm it up? To get you to burn gas and fork it over to them!!
Bucky
Oh, well. We can always make more killbots.
It’s also important not to confuse warming up, with starting it just to let it run for a while, without any intention of taking it anywhere. Driving an old army Iltis (like a camoflage volkwagon) the gas line froze because it was so excessively cold. There is also a prob with diesel fuel gelling (if your car/truck/tractor is a diesel). Of course you could save the gas/fuel and just buy gas-line antifreeze/antigel. However if you are without and leave it for a while, allowing condensation to build up in the tank, start your car up and go, there is a distinct possiblity you will stall out and maybe (like one memorable trip home from Saskatoon in a diesel) be stuck for quite a while in a teeny little town while your car warms up in a garage. 
Essentially, Keeves, ‘frigid’ is whatever you feel it is. Regardless, if you do the trouble-light thing and throw on an old blanket to help hold the heat in, you’ll find the engine starts much easier, runs smoother right away, and will reach operating temperature for the heater very quickly.
"You’ll never get as much out of being right as you will from finding out why you were wrong . . . " The Papoon Principles Ch. 1.