Warming Up the Car in Winter: Good or Bad?

Posted: December 14, 2017, 7:11 pm by askinner

Given the choice this winter, would you rather extend the life of your car or the life of the planet? The good news is that you don't have to choose! Enter the well-known myth: you should let your car warm-up before driving it in the winter. However, by skipping this pre-drive ritual, you’ll find that both your car and the environment benefit. Let’s look into where the notion came from and why it no longer holds. 

Forged in truth, a few decades ago, the carburetor was used as the mechanism to power a car, working to provide the proper air-to-fuel ratio to the engine. The catch was that if the part was not adequately warm, that ratio became skewed and the car would stall... possibly while moving. Ergo, the vehicle had to idle while the carburetor warmed up before it was safe for travel. Yet in the late 1980’s, fuel-injection technology took over using a computer to adjust the air-to-fuel ratio while the car warms. So, as long as your car was built after the late 1980’s, no longer must you fear your vehicle turning off in cold weather while driving down the road!

Why is this notion still circulated? Most would say they just don’t want to sit in a cold car; but as Tom Magliozzi, the late host of NPR’s “Car Talk” puts it, “you have your head so far up your tailpipe on this one, it may be coming out your air intake”. Well, it’s true that colder winter temperatures increase engine/transmission friction, dealing more wear and tear to your car. So, to combat friction at any time of the year, we use oil to ensure a smooth ride. Since oil works best at a certain temperature, heating it up quickly and efficiently on a cold day will minimize damage. But by letting the car idle while it warms, you essentially leave it in that wear and tear stage for longer than necessary. Instead, allow the car to do more work (in the form of driving) to generate heat at a faster rate. Overall, the best way to heat up the car's oil effectively is to turn the car on, wait 30 seconds, then drive it steadily.

While hopping into a cold car may seem like a punishment, you can feel good knowing that you’re reducing the carbon footprint of your vehicle. Similar to the fact that oil needs to be heated up in order for the car to run smoothly, the catalytic converter, which regulates greenhouse gas emissions, must also be heated in order to work properly. Skipping the cold-idle prevents about 1 lb. of carbon dioxide from entering our atmosphere. 

Need one more reason not to let your car idle while it warms up? In an effort to reduce carbon emissions from vehicles, it is actually illegal, with varying consequences, in over half of US states to let your car idle! For more info on your state's restrictions visit: https://www.epa.gov/sites/production/files/documents/CompilationofStateIdlingRegulations.pdf

 

Associate Meteorologist
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