The Columbus Dispatch

Gentle driver wants to bring on the heat

- Got a question about cars? Write to Car Talk write to Ray in care of King Features, 628 Virginia Drive, Orlando, FL 32803, or email by visiting the Car Talk website at www.cartalk.com.

for the passenger seat, Mary? Or heated underwear?

I’ll be upfront with you: I don’t know the answer to your question. Not that that’s ever stopped me from providing an answer before. But the answer’s not obvious.

You would think that by creating more friction (at higher rpm), you would generate more heat and would heat up the surroundin­g coolant a little faster. That would be my intuitive guess.

But, on the other hand, we know that one of the reasons lugging the engine (accelerati­ng from too low an rpm) is bad is that it causes overheatin­g. Which suggests that you might create more heat by shifting earlier.

So you’re going to have to run an experiment for me, Mary. Use the stopwatch on your phone. When you get into the car, record the outside temperatur­e, the weather (overcast; sunny) and the amount of time the car has been sitting since it was last used. Any of those factors can affect engine warmup time, so make sure you’re comparing apples to apples.

Then start the stopwatch when you start the car. Set the heat on full and the fan switch on high so you’ll feel the first blast of real heat when it arrives, and you can note how long it took. Try shifting at 3,000 rpm one day, and try shifting at 1,800 on other days.

Keep in mind that the thickness of the clothing you’re wearing might affect your perception of the heat. So ideally, you should run this winter experiment without pants, Mary. Purely in the interests of scientific accuracy.

My guess is that there won’t be a big difference in when the heat arrives. If that’s the case, I’d advise you to drive in a way that’s best for the car — which is exactly what you’ve been doing, by the way. By driving smoothly, accelerati­ng and braking gently, and shifting at reasonable rpm, you are doing precisely what you should be doing to make the car last longer.

And as long as it’s only the person in the passenger seat who falls asleep, you should be able to enjoy this car for many years. I look forward to seeing your results.

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