Gasoline suddenly pouring from the bottom of a moving car?

This thread: http://boards.straightdope.com/sdmb/showthread.php?t=569540
reminded me of an incident I witnessed several weeks ago on the Schuylkill Expressway outside of Philly.

I was driving home (westbound) one evening when I noticed ahead of me an object bouncing down the road. As best as I can recall (it happened fast) it appeared to be black, possibly rubber of some kind. It was bouncing in my direction but in a different lane. A number of vehicles passed over it as it bounced down the highway. Because of the height of the bounce it must have been hitting the bottoms of at least some of them rather violently.

I passed it and a little further down the highway, parked on the shoulder, was a car with a liquid pouring - not just dripping, pouring - from underneath it onto the road.

Did the object rip open their gas tank? Was the object something that had fallen off of their car, maybe some sort of fitting from the gas line?

This wasn’t in the immediate area of the bouncing object so, assuming that the two mishaps were connected, the car traveled at least a short distance after the incident. Presumably the driver lost engine power and was able to use the forward momentum to pull over onto the shoulder.

Any thoughts on what I witnessed? Could a bouncing object that fell off some other vehicle rip open a gas tank or fuel line? Could some fitting fall off the bottom of a car and cause such a large and sudden fuel leak (presumably after some incompetent repair work)?

If the engine dies at highway speeds, can a car continue traveling long enough for a driver to assess the situation, react, and navigate it to the shoulder? If not, then I’d have to assume that the engine continued to run for at least a while and the gas was pouring from the tank or the filler hose rather than the fuel line.

I’m assuming that it was gasoline due to the shear volume. Is there some other fluid that it could have been?

Any thoughts?

I had almost this exact scenario happen to me. The problem was that there was a rubber cap on some fitting attached to the gas tank. That rubber piece had developed a crack, and I didn’t notice it until I saw gas streaming out from under the car. Fortunately, I found an auto parts store about 3 blocks away, bought a replacement cap, and changed it on the spot.

It sounds like the situation you describe was a more complete failure of the same part.

Could be. Where was this cap located? Somewhere on the fuel line? What it on the bottom of the gas tank? Somewhere else?

My spelling today is abysmal for some reason. “Shear” instead of “sheer”. “What” instead of “was”. :smack:

The cap was on a tube attached to the side of the gas tank (presumably a drain or vent tube).

The replacement part was one of these (or something like it).

Makes sense. That could have been what I saw, although it’s hard to judge the size from that picture. My impression was that it was larger than what I’d imagine would be the size of such a cap, but I’m not a mechanic.

I wonder how someone would realize what was happening before they lost all of the fuel and the engine stopped. From the flow that I saw there was still quite a bit of gas in the tank when they pulled over.

Maybe air was being sucked into the fuel line? Your link does call it a vacuum cap.

I had that happen. Filled up and went to work. Got a call from security that my car was pouring out gas.

The filler pipe had broken. It only happened when it was full. I was able to drive and get it replaced.

Just on the question of driving on a highway at normal cruise speed and having the engine quit. …

If you’re not totally asleep, this is no big deal. The car will coast to a stop. But at least at first, it won’t be slowing any faster than if you just take your foot off the gas while it’s running. Which you do every day, so you’re familiar with the rate of slowing.

If you immediately start changing lanes to the right, you’ll get over to the rightmost lane before you’ve slowed more than, say, 10 or 15 mph. The just let 'er coast down to, say, 40mph then brake & pull into the shoulder.

Somewhere during the process the steering and brakes will stiffen up as the power assist wanes. But unless you’re elderly or handicapped, the effort needed to steer or brake will be no problem. More than you’re used to, but no big deal.
What you don’t have is spare time. If the engine goes from fine to dead with no warning, and you spend the next 10 seconds waking from your IPod-induced daze, then another 10 seconds wondering what to do next, well you’ll be in whichever lane on the highway doing 40, 39, 37, 35, 33, … . And other cars are now whizzing by at 30+ mph on both sides of you.

Then you’re stopped in a middle lane just hoping like hell that nobody rear-ends you at 60+ mph. And you can’t get out and make a run for it because that’s even more dangerous than staying put.

Don’t do that.

Something like that happened to me. I was on a limited access road, and a squarish scrap metal plate fell off a pickup truck ahead of me. It sort of rolled on edge under my car. A corner pierced my gas tank, making a good-sized slash. I was able to exit the road before I ran out of gas (and burst into flames) and get to a nearby place that could replace the tank. That took maybe 5 minutes.

Out of curiosity, how did you realize what had happened? Did you smell gas? Did you see a line of fluid on the road behind you?

I have two similar stories.

  1. If you’d have said that this incident happened twenty-five years ago and that the car was driving Eastbound on the Schuylkill, that would have been me. Actually, I think I hit some sort of broken pipe because it punctured my gas tank. I hit the object and then a few miles later my engine just stopped. I was able to coast over to the side of the road with no problems because the brakes and steering still worked fine. The place where my car was towed to told me that the gas tank was punctured and I needed a new one. (I believe that current gas tanks are harder to catastrophically puncture.)

  2. Just a few weeks ago my neighbor was at work when a coworker told him that his car was sitting in a puddle of gas. The repair place asked him if he had a lot of squirrels where he lived (he did) and told him that something - squirrels are apparently the usual culprit - had chewed through his gas line and that it had finally given out.