Is my Grand Marquis' fuel pump really INSIDE the gas tank?

Dear Car Talk

Dear Car Talk | Nov 01, 1992

Dear Tom and Ray:

I have a 1989 Grand Marquis with 36,000 miles on it. I have just noticed a humming noise coming from the rear end of my car. A mechanic friend told me it was coming from the fuel pump in my gas tank. I was amazed to hear of the pump?os location. Is that what it is?

TOM: Well, Bill, whenever I hear a weird humming coming from behind me, I always check the back seat first to make sure it?os not my brother doing his cajun rendition of "Danke Shoen."

RAY: But in your case, it probably IS the fuel pump, Bill. And yes, the fuel pump IS in the gas tank. They put it there for several reasons. First, it keeps the fuel under pressure all the way along the line, so the possibility of vapor lock is reduced. Second, the pump stays clean and protected inside the gas tank. If you mount it underneath the car, it?os subject to dirt and grime and squished possum and who knows what else?

TOM: And third, burying the fuel pump in the gas tank means it?os a lot harder to replace, so they can charge you a couple of hundred bucks for a new one when it starts to hum.

RAY: But it IS strange for the fuel pump to wear out after only 36,000 miles. It?os possible that a plugged fuel filter is responsible for straining the pump, and causing it to fail prematurely. But if the filter is clean, I?od say the pump was probably defective.

TOM: In which case, you should do your best to shame the Mercury dealer into paying for part of the repair. Afterall, quality is job one over there, isn?ot it?

RAY: If it turns out that quality is job two or three (behind new car sales and non-warranty work) and Mercury won?ot take responsibility for the defective pump, then spend the money and get it replaced yourself. If you don?ot, it?os going to die and leave you stranded somewhere. Good luck.

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