Drivers should only heat up their car for a maximum of 30 seconds on an average winter day to minimize fuel waste, pollution, engine wear and tear, and window fog.
Modern engines use electronic fuel injection systems and multigrade engine oils that don’t need time to warm up at low temperatures—as low as -40° F.
Experts recommend driving your car gently for about 15 minutes to prime the engine in cold weather rather than letting it idle for too long.
Americans could cut down on $5.9 billion in fuel costs if everyone took steps to reduce their winter idling times.
. According to a cold-weather study by the Government of Canada, waiting five minutes for the engine to "warm up" could plummet your fuel economy by 7% to 14%, and ten minutes could drop your fuel efficiency by 12% to 19%.
Idling increases air pollution: A 2009 energy sector study found vehicle idling made up an astounding
, half of which came from cold weather idling. That figure is twice the number of emissions caused by the entire steel and iron manufacturing industry!
Idling harms your engine: The excess gasoline that accumulates in your engine’s gas-air mixture when you leave your car running can strip oils from the cylinder walls. This decreases engine lubrication, leading to more—and faster—
According to the EPA, modern vehicles that are less than 30 years old won’t need more than:
30 seconds to get their engine warm enough for a standard cold day.
One minute to get an engine to ideal operating temperature in exceptionally frgid weather.
What to do instead: Auto experts recommend warming up your engine for winter driving by driving gently for 15 minutes right away—not idling for a few minutes.
Cold engine fact: While this is true of older cars that used carburetors to start a combustion engine, most new vehicles since the mid-1980s use electronic fuel injection systems that automatically regulate the gasoline needed to start a cold engine.
Engine oil myth: Your car’s engine oil needs time to warm up in winter weather so it can lubricate all your engine components properly.
Engine oil fact: Most multigrade engine oils recommended by modern car manufacturers are engineered to work in low temperatures down to -40 degrees Fahrenheit from start-up.
Window fog myth: Your car needs to warm up to defog your car windows.
Window fog fact: Letting your car idle actually increases fog on your windshield, since moisture typically finds the coldest place to settle—your car windows! Here’s a trick you can try to defrost foggy windows:
Turn on your car’s defogger to start clearing your windows.
Now, turn your car’s heater to high to warm up the air inside your car.
Then, turn your air conditioner on high to pull in any extra moisture in the air.
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FAQs
How long should you let your car warm on a cold day?
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The EPA recommends that drivers should restrict their cold weather idling time to no longer than 30 seconds (or a minute on really cold days). Instead, experts recommend gently driving for about 15 minutes to get your car’s engine temperature up to its optimal performance levels.
Does idling damage your engine?
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Yes: When your fuel injection system pumps too much gasoline into an idled engine, the excess gas can strip your engine of the oils it needs to operate properly. This can accelerate wear and tear on your engine.