Dear Car Talk:
I have a remote starter for my Chevy truck. I like to start the truck and let it run for a few minutes, especially during the winter. I recently read online somewhere that this is not good -- something about the car not getting enough air. Could you give me your opinion on this matter? To idle, or not to idle? -- Arturo
Idle away, Arturo -- within reason.
I've never heard of a properly functioning car not being able to get enough air. There should be plenty of air in the atmosphere for both you and your car. Of course, if you're starting your car in a closed garage or one that's attached to your house, then you're the one not getting enough air -- to your brain, Arturo. So don't do that.
But let's assume your car is outside, or in a detached garage with the garage door open. In that case, you won't do any harm to the Chevy by letting it idle for a few minutes. The car doesn't need to be warmed up before you drive it -- it's purely for your comfort -- but it won't do any harm.
In the old days, when cars had carburetors and chokes, you could harm the engine by warming it up for too long. With the choke set to cold-start mode, tons of gasoline would pour from the carburetor into your cylinders. And lots of that gasoline would go unburned, and would leak down into the oil pan, diluting the oil and shortening the life of the engine.
But modern cars are all computer- controlled, and the fuel is very precisely metered. So that's not a problem anymore. The only downsides today are that you'll be wasting gas and creating pollution. Which is why I recommend that you warm up your car "within reason."
I've got a neighbor, who shall go unnamed. But Frank goes out and starts his truck every morning -- rain or shine. Then he goes back inside, has breakfast, takes a shower and a morning constitutional, and comes out and drives away 45 minutes later. That's wasteful and ridiculous. But on 20-degree mornings, I can certainly understand wanting to get into a car that's already warmed up.
So if you want to give your car a five-minute head start on cold winter days, in our minds, that falls under the "pursuit of happiness" clause of the Declaration of Independence, and you have my mechanical, if not environmental, blessing, Arturo.