An "old husband's tale":

Dear Car Talk

Dear Car Talk | Apr 01, 1992

Dear Tom and Ray:

In order to prevent carburetor problems, my practice has been to fill up my gas tank before it gets below one-quarter full. Trying to convince my wife to do the same has been difficult. What's your opinion? Possibly, if I can show her your opinion, she might decide to do it. Thanks.

TOM: Well, you can show her our opinion, John. But after you read it, you may wish you hadn't.

RAY: This is what's known in the trade as an "old husband's tale." It goes something like this: There's a whole bunch of "crap" on the bottom of the gas tank. And if you let the tank get below a quarter full, you'll suck up the gas on the bottom of the tank and all of that crap along with it. Sound familiar?

TOM: The truth is you're always sucking up the gas on the bottom of the tank. The pick-up tube sits at the bottom of the tank. Think about it. If it sat at the top of the tank, you'd run out of gas when the tank was still three-quarters full!

RAY: This isn't to say that keeping the tank full is a bad idea. In cold climates, keeping the tank full can help prevent condensation and moisture from building up.

TOM: And in warm climates, it can prevent you from having to stick out your thumb and hitch to the nearest gas station with gas-can-in-hand.

RAY: But if engine protection is what you're looking for, the best way to keep gas tank crud from getting into the engine is to change your fuel filter regularly.

TOM: Now, John, the decent thing to do would be to take a copy of this column to your wife, fess up, and tell her you were wrong.

RAY: But we know that the parakeet is going to get to see this before she does, because you're going to put it at the bottom of the bird cage first chance you get. So after you do, at least try remember to change your fuel filter once every six months. That ought to keep you running smoothly.

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