Winter weather means that we have to do certain things that we don't usually do in the summer. Clearing the walkways, laying down salt to melt the ice, spending an extra 10 minutes layering up before you go outside, and, of course, warming up your car for a few minutes before you drive.
Everyone knows the folk wisdom that your engine needs to warm up for a bit in the cold weather because driving a cold engine can harm the lifespan of the vehicle. Some of us also do it so that the car itself can warm up and not feel like you're driving a meat freezer on wheels, and/or thawing out any frost on your windshield.
Now, mechanics and auto experts are saying this may not be the best idea, mostly due to new innovations in auto engineering. According to Popular Mechanics, a combustion engine works off a mixture of compressed air and gas vapors. The engine needs just the right mix, but cold weather can stop gasoline from vaporizing properly. In order to compensate, the system now needs to pump more fuel.
Basically, when your car sits idle in the cold, there's a risk of more unevaporated gas getting in the engine, which can be harmful because the gasoline can wash away the oil that's needed to coat your engine. Modern cars with fuel injector engines compensate for this and so there's no need to let it sit idle.
Experts recommend that you simply start your car and let it warm up for just a couple of seconds to wake up the engine fluids, but that's about it. If you have to clear the windshield, definitely do that, then get in and drive gently for a few minutes before opening her up to full speed. Do not leave it idling for 20-30 minutes, however.
For older vehicles with carburetors instead of fuel injectors, you should definitely still let the engine warm up for a while, because they don't have the technology to regulate fuel into the engine. And, of course, you can always leave the car warming up for a few minutes in order to let the windshield thaw out or the interior heat up a bit first.