Engine Warm-Ups & Air Pollution

Scientists agree: It's a waste of time and money to “warm up” your car in cold weather before starting to drive. This adds to harmful greenhouse gases.

Experts ranging from the U.S. EPA to the government of Canada and the late host of NPR's “Car Talk” program agree - warming up your vehicle's engine before you start moving has basically no benefit for your engine. Sometimes, idling can help defrost your car to a slight degree, but even then, getting the automobile moving is the ideal strategy to increase the engine's temperature.

Regardless, a 2009 scientific survey of about 1,300 U.S. residents found that on average, people think cars should be “heated up” for 5.1 minutes when the weather is wintry. That belief has meant:

  • Nationally, 13 million tons per year of unnecessary carbon dioxide emitted into the environment
  • More personal breathing of polluted air while sitting in idling autos
  • Throughout the U.S., 3.8 million gallons in wasted gas
  • For each auto, $30-$183 each year in wasted fuel
  • For each car, up to $9 per year in unnecessary wear-and-tear costs

Historically, this idea wasn't wrong, however. Before electronics in the starting and fuel delivery systems, cars used carburetors to blend air and fuel for the engine. If a car was driven cold, that blend could be incorrect and make the engine stall. Most cars now, though, have new technology. As well as saving fuel when you turn the ignition, new mechanisms track engine temperature and adjust for it. Now, you should run your engine for no longer than 10 seconds before driving.

If you stop idling, there will be many positive effects. First, your auto will run better and warm up faster. A car that is driving also begins the process of cleaning its emissions faster, using the catalytic converter. When you are just idling, the catalytic converter doesn't start working for up to twice as long, and the polluted air your car is emitting always gets to your lungs because, of course, you're just sitting in it.

If you have concerns about this or want to find out whether your vehicle needs to be warmed up before driving, reach out to the auto professionals at Christian Brothers. Avoiding idling saves time and is better for your auto, better for the air quality and better for your pocketbook.