Ask the Oil Changes Expert – Jerry Lupul
THE BIGGEST WINTER ENERGY MYTH: THAT YOU NEED TO IDLE YOUR CAR BEFORE DRIVING.
We have all heard the idea: In winter your car needs a little time to warm up before you can drive it. And that’s why, across North America, people who live in cold and snowy places—and especially those whose cars have remote starters—often fire up their engines long before they start driving. Heck, they might even start the car from the kitchen in the morning, and then only start the coffee brewing.
But it turns out that this idea of idling your car during the winter is just wrong. And so are many, many people who believe it—one 2009 study found that on average, Canadians thought they should idle for over 5 minutes before driving when temperatures were below 0 degrees Celsius!
Like many misconceptions, the idea behind winter car idling begins with a kernel of truth. Cars do get worse fuel economy when it is really cold out—they are at least 12 percent less fuel efficient, according to studies. And it does take longer for the engine to warm up and reach an optimal driving temperature in cold weather.
Moreover, older cars—which relied on carburetors as a crucial engine component—did need to warm up to work well, according to several auto industry Experts®. Without warming up, the carburetor would not necessarily be able to get the right mix of air and fuel in the engine, and the car might stall out.
During the 1980s and into the early 1990s, however, the auto industry did away with carburetors in favor of electronic fuel injection which uses sensors to supply fuel to the engine and get the right air and fuel mix. This makes the problem of warming up the car before driving irrelevant because the sensors monitor and adjust to temperature conditions.
Idling in winter thus has no benefit to your (presumably modern) car. Auto Experts® today say that you should warm up the car no more than 30 seconds before you start driving in winter. “The engine will warm up faster being driven,” Indeed it is better to turn your car off and start it again than to leave it idling.
So idling does nothing for your vehicle, but it does have several big (and avoidable) costs: Wasting fuel, and giving off greenhouse gas emissions and other types of pollution.
To show how much Natural Resources Canada ran an idling experiment, freezing three cars to -18 degrees Celsius and then driving each one the same distance. Sometimes the cars were idled five minutes before driving, and sometimes 10 minutes. The result was that the more idling time, the more fuel wasted.
The test results showed that with a five minute warm-up total fuel consumption increased by 7 – 14% and with a 10-minute warm-up total fuel consumption increased by 12 – 19%. Also of note, the bigger the engine the more fuel is wasted.
Next month I will talk about the damage to the inside of your engine that idling creates. Just because you do not see it does not mean the damage does not occur. Talk to you then.
Sources: Chris Mooney’s article “This is why people still think they should idle their cars in winter” in the Washington Post York University’s “If you think idling is harmless, think again” www.edf.org “Attention drivers! Turn off your idling engines”
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