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SIOUX CITY -- In the frozen Midwest, starting the car early and letting it idle for five, 10 or 15 minutes seems as necessary as gasoline or oil changes.

Wintertime idling is something everyone does, without question. Mom and Dad did it, and so did Grandpa and Grandma, and their parents. Great-Great Grandpa let the horse idle for half an hour. 

What unthinkable thing would happen if, on a zero-degree morning, you just stepped on the gas and let it fly? Probably the engine would burn up, the gaskets would melt, a piston would shoot through the hood, the transmission would get pneumonia. 

It's not a concept most cold-weather people are comfortable with. 

But is it actually necessary to let the car idle? Is there a sound, scientific reason to idle the car -- or is it just a misconception? 

Depends who you ask. And what kind of car you drive. 

In ye olden days, when cars had carburetors, cold weather idling was more or less necessary. Pump the pedal to the floor before starting your 1980 Oldsmobile Omega (to set the choke), pray the engine achieves ignition when you turn the key, then let it idle. 

Those fussy, fussy carburetors. Perhaps it's not surprising that an engine that couldn't ignite when it was flooded with gasoline also doesn't have much get-up-and-go in cold weather. 

In the late 1980s, Motor City engineers came up with electronic fuel injectors, and the tyranny of the carburetor engine was toppled. This new fuel-disbursement system lacked the drawbacks that carburetors had -- in particular, they weren't nearly as miserable in cold weather. 

Yet for whatever reason, people continued idling their engines in the cold. 

Mechanics weigh in

Curt Blankenburg, an assistant manager at Knoepfler Chevrolet, says modern cars (with their fuel injection and motor oil that resists congealing) don't need the coddling that older cars did. 

"At one time, I think there was some value in letting your car idle when it was cold outside, you know back when we had carburetors," he said. 

Blankenburg said the only reason for letting a modern car sit there and burn gasoline in the cold "is for your own comfort" -- i.e., the heater starts working. 

"Actually driving it gets your car warmer than just sitting there, leaving it idle," he said. 

Joe Brockelsby, a senior tech at Mac's Auto Repair, doesn't entirely agree with this assertion. When it's bitterly frigid, he says an engine would benefit from a few minutes of idle warmth. 

"Well, when it's really cold out, all the fluids in the vehicle get stiff and thick, and it's harder for the car to push them, so if you let it run for even just a minute, it allows that stuff to loosen up and flow better," Brockelsby said. 

But will the motor have a meltdown if you don't let it run? Probably not. 

"I would say that, you know, over the long run, it is going to cause more engine wear to your car," he said. 

Other sources vary widely in their opinion of the practice. According to a Firestone Complete Auto Care blog post and an article in Popular Mechanics, it's bad for the engine to let it idle in the cold -- the gasoline could strip the oil from cylinder walls.

Still others note, even if idling isn't damaging, it's unacceptably wasteful -- after all, a car running in idle is getting zero miles per gallon. 

Car theft

There is another, major downside that people don't always think of when they leave their cars idling -- a car left running alone is prone to being stolen. 

In the past few months, a few high-profile car thefts have struck Sioux City: in one case, a car was left idling, stolen, then left idling again for a day and a half. Just a few days later, another idling car was stolen with a child inside. 

Jeff Harstad, a detective with the Sioux City Police Department, says car thefts are fairly common in the wintertime, when people leave their vehicles running. 

"The problem is they're leaving them unattended," Harstad said. "During the winter months we definitely see an increase in stolen vehicles." 

Most vehicles stolen in the winter are later found, Harstad said -- they're taken by opportunist thieves from point A to point B, and then abandoned. But not everyone is so lucky. 

"We definitely have people that steal cars with the intent to chop them, or to dismantle them or sell them," he said. 

Harstad said the department strongly recommends people not leave their vehicles running unattended -- cars have been stolen in front of homes and at gas stations. 

"Don't do this; we're seeing them stolen at all locations, all around the city," he said. 

Usually the victims never see it coming. 

"They say, 'Oh I didn't think it was going to happen to me,'" Harstad said. 


Lifestyles reporter

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