Ask a Technician: Should I Warm My Car Up before Driving in Winter Weather?
The daily morning car-warming ritual is carried out faithfully in most parts of the country from late November to early March. But is it necessary? The answer is: it depends on your needs.
The purpose of warming up your car. The main reason drivers start their car and let it idle is to warm it up by getting the oil circulating through the engine. Modern fuel injection systems, however, with the elimination of carburetors and chokes, have made engine idling unnecessary. After about 30 seconds, the oil is circulating and your car is ready to go. The Hinkle Charitable Foundation's Anti-Idling Primer, in fact, asserts that idling forces the engine to operate in an extremely inefficient mode, which can harm the engine's performance and lower its mileage. If you're still skeptical, drive a little slower for the first mile or two instead of idling.
Warming up the inside. Many commuters couldn't care less about engine efficiency at 6:00 AM when it's frigid cold. Instead, they just want a semi-warm vehicle to step into when it's cold. Idling your car will use more fuel than if you warm up your car by actually driving it, but this may be worth it if you are driving with small children or older adults. If you really want to be on the cutting edge, some modern cars allow you to pre-warm the vehicle via remote access without ever having to idle.
Idling and the environment. Still not convinced about the inefficiency of idling to warm up the vehicle? Perhaps you think engine inefficiency is a small price to pay for not freezing your fingertips when you enter your car. Maybe a look at environmental effects will unfreeze your stance. Exhaust is harmful to human health, especially children. Certainly, exhaust is a necessary component of driving a car, but unnecessarily spewing exhaust adds to air pollution. Avoid idling close to curbs and sidewalks, where pedestrians and children are at risk from the negative effects of exhaust.
The cost of idling. If air pollution and the potential harmful effects of unnecessary exhaust don't convince you to cut down on idling, perhaps the cost of gasoline will. Idling wastes gas. Gas costs money, therefore idling wastes money -- your money. Motorists are advised to turn off their engine when idling more than 10 seconds (traffic stops excluded). You'll save money. You'll save the environment. You'll save your engine. (A new engine, by the way, costs money too. A lot of money.)
Proper car warming procedures. Don't stand by idly and let this information go to waste. If you're worried about your engine's performance, warm the car by driving it slowly. If you're worried about being cold when you hop in the car, bundle up, start the car, adjust the radio, turn on the heat and get going.