Dear Car Talk:

I live out in the sticks, where my neighbor John and I are good friends. I have a spare garage, where, out of the kindness of my heart, I allow John to park his Mini Cooper. Well, it's been cold lately, and John commutes an hour to his job. So before his trip each day, John made a habit of warming up his car in my garage, with the garage door closed. Now, my garage is no luxury accommodation, but it does have carpet on the walls (it was that way when I bought it), and it is in fairly good shape, generally speaking. I'm concerned that the emissions from John's car are gradually making the inside of my garage a grimy mess. I assume that John is concerned with getting his car warmed up as quickly as possible. I've asked John to open the garage door while he warms up his car, but he's being stubborn. Being the consummately reasonable man I am, I informed John this morning that I would submit this question to Car Talk and live by the verdict: Am I being neurotic, or is John being a jerk?

-- David

Car Talk: Well, if he's sitting inside the car while warming it up in a closed garage, you won't have to worry about this problem for much longer, David. Just make sure John leaves you the Mini in his will so you won't have to move it. 

Honestly, I think John's being the jerk here. It is going to make your "wall-to-wall" carpet grimy over time. And if that bothers you, he shouldn't do it. It's your garage, and if you want the door open when he's creating fumes, he's a guest and he should respect that. When my brother used to come to my house for dinner, I always insisted that he open a door when he was creating fumes, too. 

Besides, John's not warming up his car faster anyway. From your description, I'm assuming this is an unheated garage. If that's the case, the car won't really warm up measurably faster with the door closed. By the time morning rolls around, it's the same temperature inside the garage as it is outside --carpet notwithstanding.

And he shouldn't even be warming up his car, anyway. I mean, if it's below 20 degrees out, then you can warm up the car for a minute before you start driving. But otherwise, all you're doing is wasting gas and creating pollution.

Above 20 degrees, the right thing to do is to just start the car and drive it. Driving gently is the best, and fastest, way to warm up a car. 

Of course, he could be warming up the car for the benefit of his feet rather than the engine. He may start the car, go home for coffee, then come back once the passenger compartment is 90 degrees -- in which case he's just wasting even more fuel and creating extra pollution. And in which case, he'll have to do it with the garage door open. 

Car Talk has spoken, David. And if you want to make the point more strongly about the downside of fumes in closed spaces, invite yourself over to John's house for dinner and explain it to him.