The Facts Behind Idling Your Car's Engine

Scientific studies reveal the truth: You shouldn't “warm-up” your in the winter before hitting the road. This adds to harmful greenhouse gases.

Groups from the Environmental Protection Agency to Natural Resources Canada and the late host of NPR's “Car Talk” program agree - warming up your vehicle's engine in the driveway has virtually no benefit for your car's engine. Sometimes, letting the engine run can defrost to a slight degree, but even then, actually driving the car is the most efficient method to up the engine's temperature.

Nevertheless, a 2009 study of 1,300 U.S. residents found that, people believe that automobiles ought to be “warmed up” for 5.1 minutes when the temperature is below freezing. This myth has led to:

  • For each vehicle, up to $9 each year in unnecessary wear-and-tear costs
  • Increased personal exposure to pollutants while sitting in stopped cars
  • Nationally, 13 million tons per year of unnecessary carbon dioxide emitted into the environment
  • On a national level, $5.9 billion per year in wasted gas
  • For each auto “warmed up”, up to $183 per year in wasted gas

The beginnings of this idea that cars and trucks need to be heated up are based on a time when it was true. Before electronic starters and electronic fuel injection, automobiles used carburetors to mix air and fuel for the engine. If a car had not been warmed up before being driven, that blend could be incorrect and make the engine stall. Almost all new cars have updated technology. As well as conserving gas at startup, electronics track engine temperature and adjust for it. Now, it is widely agreed by experts that you should run your car for 10 seconds or less before hitting the road.

If you stop idling, there will be many benefits. Your car or truck will work better and heat up faster. A car or truck that is driving also starts the process of cleaning its emissions more quickly by way of the catalytic converter. When you are just idling, the catalytic converter doesn't start working for about twice as long, and the dirtier air always gets into the cabin because, obviously, you're stationary.

If you have questions about whether your auto needs to be warmed up in the winter, contact the auto professionals at Christian Brothers. Not idling saves time and is better for your car, good for the environment and better for your budget.