The ritual of fully warming up a car in the winter is actually a holdover from the days of carburetion — to prevent stalling, the cold metal needed plenty of warming time before it reached optimal temperatures. These days most fuel injection systems are sophisticated enough to make the appropriate adjustments for blustery conditions. There’s also little reason to worry about whether your engine oil and other fluids will operate in cold weather; synthetic products manufactured today are designed to provide protection even when the mercury dips below zero. Basically, modern cars have evolved to the point that a driver’s discomfort and external road conditions are the main safety risks in cold weather — especially if you’ve done your research about proper tires for the season.
Fuel injected vehicles generally need only 30 seconds of warming up before they are ready to go, even in cold weather. After that, the best way to increase your engine’s temperature is by driving the car. Not only will this get hot air into your cabin faster, it saves gas and cuts emissions. If temperatures dip to 10-20 degrees Fahrenheit or lower, warm the car for a minute or two to ensure the oil thins and circulates fully.
Even though your engine only requires a minute, you may want extra warm-up time to thaw the rest of the car. The best method for this is to start your car, turn on the defroster and let the engine warm while you scrape the windshield and clear away snow. Try not to idle for longer than five minutes to conserve fuel, and check to see if your region has a limit on idling time.