NWautos: Seattle's local source for new and used autos


November 13, 2011 12:00 AM

Tom and Ray crack the case of a fuel pump gone bad

Dear Tom and Ray:
I live in Houston, and on a typical 104-degree day this past summer, I took my son's car to run some errands and stopped first to fill the tank. I then drove to my first stop, about 15 minutes away, and went in to shop. I was there about an hour. I came out, started the car and it rattled and died. I tried starting it multiple times, but it just didn't seem like it was getting any fuel. I walked over to a nearby auto-repair chain, told them my story and the guy asked me if my tank was empty when I stopped for gas. Well, it is my son's car, so of course it was empty! He immediately said that I had cracked the fuel pump by putting cold gasoline into a hot gas tank. Well, $650 later, the car is running again, but everyone I have told this to says I was scammed. Was he telling me the truth, or just shining me on?
-- Hart

Ray: Wait a second, Hart. I'm writing down this story. I may be able to make a few boat payments with this "cracked fuel pump" idea.

Tom: We've never heard of a cracked fuel pump, Hart. The housing of the fuel pump is metal. So I find it hard to believe that it would crack if it came into contact with 50-degree gasoline.

Ray: Maybe he meant that the plastic impeller cracked -- that's the internal part of the pump that actually pushes the fuel. Even then, I've never seen that happen due to "cold" gasoline. It just happens due to age and use.

Tom: But assuming they tested your fuel pump and it was dead, and that replacing the fuel pump has solved the problem, I'd have to conclude that this guy was right. At least his diagnosis was correct, even though his explanation was nutty.

Ray: I assume that since this is your son's car, and he always has the tank on E, it's not exactly a brand-new model. On a high-mileage, older car, anything can go wrong at any time. I think the fuel pump just happened to die that day.

Tom: But not because you filled up the tank. If fuel pumps regularly cracked when gas was added on hot days, what would people in Houston do all summer? Push their cars around until things cooled off in the fall?

Ray: Seems unlikely. But fuel pumps do fail. And if you are satisfied that they actually did replace your fuel pump for the $650, and that fixed it, I think the timing of the fuel pump's demise was just a coincidence. So feel free to get gas next summer.

(Car Talk is a nationally syndicated column by automotive experts (and brothers) Tom and Ray Magliozzi. Write to them at the Car Talk website.)