The Biggest Wintertime Myth: That You Need To Idle Your Car Before Driving

Posted On: Thursday, February 11, 2021

A popular belief among car owners is that they need to let their car warm-up for several minutes before setting out on their drive. The idea behind this is to let the car’s engine get up to temperature by running idle for a few minutes, all to protect the engine’s longevity and performance.

The reality of things, however, are different. Idling your car for a few minutes wastes not only your time but also wastes valuable fuel. Crucially letting your car engine idle at freezing temperature has the potential to wreak havoc on your engine and shorten its life.

Why Many People Think Idling Cars During Winter Is Paramount

Internal combustion engines run by mixing gasoline with air within the engine’s cylinders. Once the air-fuel mixture is compressed, the mixture is ignited by the spark plug, which moves the pistons. In the years past, specifically before the 1980s, a carburetor controlled the mixing of fuel and air. One shortcoming of the carburetor was its inability to control the fuel in the air-fuel mixture precisely.

Given that gasoline has a hard time evaporating in cold weather, the carburetor was susceptible to releasing a lot more fuel than necessary. The fuel-rich mixture increased the potential for engine damage once ignited. To negate the risk of engine failure, car owners were advised to idle their car for a few minutes to allow the engine to warm up (https://www.washingtonpost.com/news/wonk/wp/2014/12/29/the-biggest-winter-energy-myth-that-you-need-to-idle-your-car-before-driving/), and, therefore, make it easy for the carburetor to supply the right fuel mixture.

Why It’s Better To Run Your Modern Car Rather Than Idle The Car

Since the 1980s, car manufacturers moved away from using carburetors to a more advanced system – the electric fuel injectors. As such, the car is fitted with sensors that measure the outdoor ambient temperature. This system allows the electric fuel injector to adjust the air-fuel mixture to account for the cold weather. Typically, an electric fuel injector will create a fuel-rich air-fuel mixture by releasing more gasoline, compensating for low evaporations levels.

With this in mind, when you idle your car, you are burning more fuel with little to no benefit. After all, your car’s engine has been optimized to operate in cold temperatures without the car stalling. The only reason to idle your car is to warm up the cabin and defrost the windshield, which should take about 3 minutes.

Why Idling Your Car Is Harmful To The Car’s Engines And The Environment

Idling your vehicle for 10 to 15 minutes before starting your journey will increase pollution. With a lot of the fuel exiting the engine unburned or partially burned, your car will release a lot of toxic fumes. Moreover, idling your car will increase the engine’s wear and tear, reducing its longevity (http://www.businessinsider.com/heres-what-idling-your-car-in-the-morning-is-doing-to-your-engine-and-its-not-good-2016-1). For starters, the extra unevaporated gasoline will attack the lubricating oil in the engine, decreasing lubrication and increasing metal to metal rubbing. Consequently, it will shorten your engine’s life significantly.

Click to learn about some of The Best Fuel Economy Tips For Winter Driving