In the thick of winter, the common wisdom is that when you are gearing up to take your truck out in the cold and snow, you should step outside, start up your engine, and let it idle to warm up.
Some drivers jump in and sit patiently, while others immediately hit the accelerator and head on their way. Most vehicles built before 1995 used a carburetor, a device that combined air and fuel. In the '80s and '90s, manufacturers changed over to a fuel injection method, eliminating the need for a carburetor. 
With a carburetor, it was essential to let the car lie idle for minutes before driving it in order to make sure the engine would run properly. But with modern cars, it's not the engine itself that needs to be warmed up when it's cold outside.
There are pros and cons either way on this and experts are torn on this issue. Some say the car can be driven immediately, just at a neighborhood speed. Others argue that cars need to idle for a couple of minutes to get the oil properly flowing. "The oil is the lifeblood of the engine," Joseph Henmueller, president and COO of Automotive Maintenance and Repair Association, said. He suggested that cars should idle one to two minutes before driving in cold weather. When temperatures drop to freezing, or when it's cold enough that the 
windshield will frost over, the oil needs to warm up before it can move smoothly throughout the car.
"Fluids get thicker when it is cold, so to lubricate properly they need 60 to 120 seconds of the engine running," he said. Experts at Penzoil have a different theory. Technical Adviser Shanna Simmons said it is a myth that engines need to sit idle on a cold winter day. "While it does take longer for engine oil to pump in extreme cold temperatures, we are talking milliseconds, not minutes," she said. "Your engine will warm up the oil much faster when driving at full speed — not to mention idling wastes gas." In a nutshell, an internal combustion engine works by using pistons to compress a mixture of air and vaporized fuel within a cylinder.
The compressed mixture is then ignited to create a combustion event—a little controlled explosion that powers the engine. When your engine is cold, the gasoline is less likely to evaporate and create the correct ratio of air and vaporized fuel for combustion. Engines with electronic fuel injection have sensors that compensate for the cold by pumping more gasoline into the mixture. The engine continues to run rich in this way until it heats up to about 40 degrees Fahrenheit. Driving your car is the fastest way to warm the engine up to 40 degrees so it switches back to a normal fuel to air ratio. Even though warm air generated by the radiator will flow into the cabin after a few minutes, idling does surprisingly little to warm the actual engine. The best thing to do is start the car, take a minute to knock the ice off your windows, and get going. 
So, if you're not supposed to let your car idle in cold weather, then what are you supposed to do? Experts suggest that the best way to get your car warmed up is by simply hopping in and taking it nice and slow. Worried about how turning your car on and off might affect your engine, particularly in the winter? If you need to run a few quick errands, such as stopping to purchase a newspaper or pick up the mail at your PO Box, it may be tempting to keep your car running, however, it's better for your car, and the amount of gas you use, to turn off your car. To sum it up…Warming up your car before driving is a leftover practice from a time when carbureted engines dominated the roads. Carburetors mix gasoline and air to make vaporized fuel to run an engine, but they don't have sensors that tweak the amount of gasoline when it's cold out.
As a result, you have to let older cars warm up before driving or they will stall out. But it's been about 30 years since carbureted engines were common in cars. Today, most manufacturers say it is best to minimize letting your car engine sit idle. It will warm up faster being driven, which will allow the heat to turn on sooner, decrease your fuel costs and reduce emissions. Feel free to leave comments and be sure to hit the “Like” button at the bottom of this post.
