Why You Shouldn’t Idle Your Car in Cold Weather

December 27th, 2022 by

Winter is officially here in Chicago, which means drivers are waking up to frosty roads, icy windshields, and stone-cold engines. In frigid temperatures, many drivers will habitually start their engine and idle their car before hitting the road to ‘warm up’ the vehicle. Some cars even have a preset feature that allows drivers to start their cars remotely.

However, despite this commonly held belief, your car doesn’t need to warm up in cold weather, particularly if it was made after 1980. In fact, excessive idling in winter temperatures could potentially damage your engine.

If you’re one of the many drivers who believes it’s important to idle your car before driving in wintry weather, read on to learn why it’s time to change this habit.

Where Did the Idling Myth Come From?

The outdated belief that a car should be idled in cold weather to ‘heat up the engine’ is based on the way that most cars were once manufactured. Before 1980, most vehicles did need to warm up in the winter. This was because most of them had carburetors. Carburetors regulated the air-fuel mixture within the engine and couldn’t accurately adjust the air to fuel ratio in cold weather. In order to properly operate, the carburetor needed to warm up or else the vehicle would run the risk of stalling out.

Nowadays, nearly every car sold in the United States has an electric fuel injection system that helps maintain the ideal air-fuel mixture needed for a combustion event, regardless of the ambient temperature. In other words, the sensors in your car’s electronic fuel injection system are regulating the air-fuel mixture in real time, regardless of the temperature outside.

Reasons to Avoid Idling in Winter 

Changing habits can be tough. But before you concede to falling back on old habits, check out the following reasons why idling your car on a cold day could be doing more harm than good:
• It Causes Engine Damage. Idling your car in cold weather not only wastes gas, but it’s also stripping oil from critical components that help your engine run, namely cylinders and pistons. Less oil means more friction, more wear and tear, and ultimately a shorter lifespan for your engine.
• It’s Illegal. Under Illinois law, it is illegal to leave your car running and unattended, a law designed to help prevent car theft (regardless of the season).

• It Costs You Money. Aside from the damage you could be inflicting on your engine and the subsequent repair costs, idling wastes lots of gas. Unnecessary idling consumes fuel and produces emissions even while the car is stationary. A 2009 study in Energy Policy estimated that Americans waste approximately $5.9 billion a year on gas while idling.

• It’s Bad for the Environment. According to the same Energy Policy study, idling cars produce a staggering 1.6% of the country’s total greenhouse gas emissions. Much of the pollution from idling cars ends up reducing air quality and contributing to urban smog.

What to Do Instead

Most automakers recommend that drivers pull off gently after 30 seconds in the wintertime. Ironically, the engine will warm faster this way, which allows the heat to turn on sooner while also lowering your fuel costs and reducing emissions. By letting your car sit to warm up, it’s actually placing extra fuel into the combustion chamber which can then get onto your cylinder walls. Because gasoline is an excellent solvent, too much of it on your cylinder walls can dissolve the oil that lubricates your cylinders, leading to shorter life on crucial components. Driving your car normally and avoiding hard acceleration will bring the engine to a warmer temperature faster. In fact, manufacturers maintain that vehicles with modern fuel injection systems can be driven immediately on startup with no need to delay.

Drivers should start the engine and allow their car to idle only for the time it takes to fasten their seat belt. This amount of time ensures lubricating oil gets to all of your engine’s vital parts. This means that your winter driving routine should look something like this: bundle up, start your car, scrape off your windshield, buckle up, and start driving.


Do you have questions about maintaining your car’s engine in cold winter weather? Our highly trained service technicians are happy to help.

Give us a call at 888-534-2003 or schedule a service appointment with our Online Service Scheduler!


Posted in Automotive