ROCKFORD, Ill. (WTVO) — As temperatures plunge across the Midwest, many drivers still cling to the old habit of letting their cars idle for several minutes before hitting the road. The reasoning seems sound: a warm engine and a cozy cabin make for a better commute. But is it necessary or even good for your car?

The practice of warming up your car dates back to the era of carburetors, which dominated vehicles until the 1980s. Carbureted engines needed extra time to stabilize the air-fuel mixture in cold weather, preventing stalling and sputtering. Today’s vehicles, however, use electronic fuel injection systems that automatically adjust for temperature, making long warm-ups largely obsolete.

Modern engines are designed to circulate oil quickly and reach operating conditions without prolonged idling. AAA recommends starting your car and letting it idle only for the time it takes to fasten your seat belt—about 30 seconds. This brief period allows oil to lubricate critical components. After that, driving gently warms the engine faster and more efficiently than idling.

Consumer Reports agrees, noting that engines are fully lubricated within 20 to 30 seconds of starting. Extended idling wastes fuel, increases emissions, and can even cause unnecessary wear on engine parts.

The Environmental Protection Agency warns that idling contributes to air pollution and burns fuel without moving the car. Studies show that idling for 10 minutes can waste up to a quarter of a gallon of gas, adding up over a winter season.

There are a few scenarios where a slightly longer warm-up may help:

• Extreme cold: In sub-zero temperatures, idling for one to two minutes can help fluids reach optimal viscosity.
• Older vehicles: Cars built before the 1980s with carburetors may still need two to three minutes of idling.
• Heavy towing: A short warm-up can prevent overheating under load.

Electric vehicles are a different story. Cold weather reduces battery efficiency, so EV owners should precondition their cars by warming the battery and cabin while plugged in, before driving.

In addition, leaving your car running unattended can make it an easy target for thieves. Police departments report spikes in vehicle theft during the winter months when drivers leave cars idling outside homes or workplaces. If you use remote start, ensure it has an anti-theft feature.

For most modern cars, the best practice is simple: start your engine, wait about 30 seconds, and drive gently. Prolonged idling is unnecessary, costly, and harmful to the environment. If you need a warm cabin, consider seat heaters or remote start systems—but don’t fall for the outdated myth that your car needs 10 minutes to “wake up.”