Cops, TNCC auto expert: There are a few reasons why ‘warming up’ your car is a no-no

Temperatures are continuing to drop, but despite what you’ve heard, police in Hampton and an automotive technology expert at Thomas Nelson Community College agree — the risks of starting your car to let it “warm up” in the winter outweigh the benefits.

Not only is it a violation of Hampton city code to leave a vehicle unattended with the key in the ignition but the department recently produced a social media video and said the practice makes your car an easy target for criminals.

“It’s a really bad idea to start your car and leave it running unattended,” they said.

Outside of it being illegal and making your vehicle more susceptible to thieves, Marc Burge, TNCC’s Automotive Program head, said unless the car was manufactured before the 1990s it’s unnecessary, and may even be harmful, to leave a running engine idle for more than five minutes.

“There’s a potential, especially in colder temperatures, to have incomplete combustion which can cause the fuel to get into the oil and become diluted and polluted sooner than if you drove it,” he said.

Fuel injection technology in modern vehicles allows them to “warm” or get coolant circulating within about 30 seconds to a minute which Burge said is different from the days when carburetor vehicles needed time to avoid stalling out.

The newest technology has evolved to prevent idling by automatically turning cars off if they’re sitting at a red light or are in standstill traffic which otherwise would “kill fuel economy,” Burge said.

“Miles per gallon will deplete…at 20 minutes your fuel economy will drop back to zero in a best-case scenario,” he said. “This technology has the potential to increase fuel economy anywhere from 3 to 10 percent.”

In a worst-case scenario, Burge said starting a vehicle and allowing it to sit running can also potentially lead to the expensive repairs of corrosion in the exhaust system or in the long term, converter overload caused by an oil and gas mixture.

“A lot of convenience with late-model vehicles and the key fob is the remote start feature…if you hit the button in the house and are out within about two minutes, you should be good to go,” he said.

Click the video to watch Hampton Police Division’s public service announcement about theoretically putting a “free car” sign on your vehicle this winter.

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