The mysterious, 140 year-old, never-changing automotive part.

The Puzzler

RAY: The device is most commonly found in the stem of your tires, and it's called a Schrader valve. It's a little valve that keeps the air in, and allows you to add more air by depressing the stem of the valve, or let air out if need be.
Right now, you're probably saying, "My car has four tires and a spare. How can I have six or seven of these valves?" Well, your air conditioning system has one, and lots of cars have one as a test port in the fuel rail, to be able to hook up a pressure gauge.

So, your car could easily have seven of these, even though it has only five wheels. Do we have a winner?

TOM: We do! The winner this week is Alison Haskins from Oxford, Ohio. And for having her answer selected at random from among all the correct answers that we got, Alison gets a 26-dollar gift certificate to the Shameless Commerce Division at, where she can get her mom a copy of our mothers and cars CD collection, called 'Maternal Combustion.' Actually a gift like this might be better for your mother-in-law. Nothing says, "I'm not really that fond of you," like a Car Talk CD. Don't you think?

RAY: Well, that's true.

[ Car Talk Puzzler ]

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