Should I let my car idle before I drive it?

Dear Car Talk

Dear Car Talk | Apr 01, 1990

Dear Tom and Ray:

I start my car and immediately drive away at moderate speeds. My neighbor to the left starts his car and lets it idle for five minutes before taking off. My neighbor across the street takes her car out of the garage and lets it idle for an hour before leaving for work. Who is right, who is wrong, and why?

TOM: This is one of the great questions of all time, Gina, and YOU are the one who's right! The best way to warm up a car is by driving it at moderate speeds. If you put the car in gear and it doesn't stall, it's ready to drive. There are, however, two situations in which your neighbor to the left would be correct.

RAY: In extreme cold--that is, sub zero temperatures--it's appropriate to let the car warm up for a few minutes before driving it. Oil gets thicker in very cold weather, and allowing the car to idle for a few minutes ensures that the oil warms up and thins out enough to coat the cylinder walls.

TOM: You might also want to warm the car up for a few minutes if you had to drive at high speeds right away. For example, if you live right at the entrance to a super highway, it would be a good idea to let the car idle for five minutes before getting on the highway and driving at 55 mph.

RAY: While it's warming it up, you could read the real estate section of the paper to see if there are any apartments in better locations.

TOM: Or, while the car is warming up, go across the street and peek into the window of your neighbor's house. When you find out what she's doing for an hour while her car warms up, write to us again because we're dying to know.

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