A half full or half empty tank.

Dear Car Talk

Dear Car Talk | Dec 01, 1990

Dear Tom and Ray:

First of all, I really enjoy your column, even though I'm not a "car person." I own a 1983 Volvo DL wagon. It has 125,000 miles on it, and it runs well. My problem is that when the tank gets almost half empty, the car will stutter and die until I fill it up again. Once it's filled up, it runs smoothly. I have owned it for 8 years and love it a lot, but I have not always had the money to take the best possible care of it. Now is one of those times. I would like to continue to drive it for at least another five years or 75,000 miles. Am I hurting it by not having it fixed? And what's the problem?

RAY: It sounds to me like you need a new pre-pump. Your Volvo has two fuel pumps, one in the gas tank, and one outside the tank. When the tank is more than half full, the outside pump works fine. But when the tank gets closer to empty, it needs the pre-pump to help push the fuel out.

TOM: Since your pre-pump isn't working, not enough gas is getting to the engine, and that's what makes it stutter and die.

RAY: And while you may not be doing any irreparable damage by not fixing it now, you may end up spending more money if you wait. After a while, you'll not only need a pre-pump, you may burn out the regular pump too.

TOM: But we think that's a good thing, Judith. We can tell you haven't been spending nearly enough annually on your Volvo repairs. I'm surprised you haven't gotten a nasty letter from the Volvo owner's association. You're pulling the national average way down!

RAY: So when you go in for the fuel pump, take some corrective action. Ask for a new transmission, a timing belt, some control arm bushings, some trailer arm bushings, and a rear main seal. That should cover your contribution to Volvo for the first half of the year.

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