Warming Up Your Car

Physiologically speaking, the benefits of warming up your car are clear: When the temperature drops into the single digits or into the negatives, driving isn't comfortable. On the other hand—mechanically speaking—the benefits of warming up your car aren’t so clear. When it’s cold outside, should you spend extra time warming up your car? If so, how long should you let it run?

Obvious Reasons to Warm Up Your Car

Warming up your car improves combustion, fuel economy and performance. The engine's cooling system uses a thermostat to maintain its most efficient temperature range, usually around 200 degrees Fahrenheit. This operating temperature is where the fuel vaporizes best. Warming up the engine also improves lubrication and hydraulic efficiency.

Surprising Reasons Not to Warm Up Your Car

Many places have implemented idling laws, not because they want you to freeze, but because the environmental risks are far more disastrous. Warming up your car is a waste of fuel, generating excessive emissions even before you actually drive. Having your car idle for a long time can also increase engine wear.

How Long Should You Keep It Running?

What we really want is the best of all situations. We don’t want to be pumping out extra emissions for no reason—cold engines generate hydrocarbons, carbon monoxide and nitrogen oxide emissions. At the same time, no one wants to freeze their glutes off in a frozen car. So just how long should you warm up your car?

For lubrication, hydraulic function and fuel vaporization, one or two minutes should be enough to get moving. Pushing warm-up time to five minutes doesn’t really add much warming, but it could make scraping your windshield easier.

To get your engine to operating temperature faster for best fuel economy, emissions, performance and cabin heat, you have to get out on the road, but take it easy for the first five to 10 minutes. In subzero weather, using a block heater a couple of hours before you start your engine gives warming a head start.

For more information on how long you should warm up your car, and to check out heating and cooling system parts, head to your local NAPA Auto Parts store, a Discounts & Rewards official partner.