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Dear Car Talk

Dear Car Talk | Mar 01, 1992

Dear Tom and Ray:

My wife and I need you to resolve a disagreement we're having. When we get into our '88 Dodge Caravan on a cold morning, my wife wants me to turn on the heater immediately. She says that way, the inside of the car gets warmer quicker. I say that the engine is cold, and allowing it to heat up a bit before turning on the heater will ultimately get us warmer faster. We know you'll resolve this difference with your lucid, irrefutable responses.

TOM: You know, Will, this is what separates us from the baboons. You don't see baboons sitting around the coffee table in the living room contemplating issues as deep as this.

RAY: Actually, Will, it's a very good question. There's not a person with a heater who hasn't wondered the exact same thing. And now that you've brought it out into the open, you've given us the opportunity to answer this question for millions, if not hundreds of millions of people all over the world.

TOM: And the answer is, it doesn't really make much difference.

RAY: Technically speaking, your wife is correct. If the heat is on, then the moment any heat is produced by the engine, it will come into the passenger compartment.

TOM: Of course, that also means having to endure all that cold air blowing on your tootsies while you wait.

RAY: But "when YOU get heat" may not be the question you should be asking. A better question might be "what's best for the car?" And again, although the difference is slight, it's better for the CAR if you leave the heat off at first.

TOM: The heater core--which delivers heat inside the car--is nothing more than another radiator--just smaller. And like the radiator in the front of the car, it drains heat and cools off the engine. And why would you want to cool off the engine when you're trying to warm it up?

RAY: You want the engine to reach operating temperature as soon as possible, so it'll run most efficiently. And draining the small amount of heat it produces while it's first warming up simply increases its warm up time.

TOM: So your method is correct, Will, even though her theory is correct. The solution seems simple to me. Leave the heat off for the first few minutes while the engine warms up. And during that time, YOU snuggle with her and keep her warm.

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