Gas pump didn’t stop when full – Should I be concerned?

Imagine the following scene: you’re sipping gasoline without a care in the whole world. Suddenly, you notice your tank or gasoline container overflowing. It seems as though the gas pump didn’t stop when full. For some reason, the mechanism didn’t work this time. You wonder: okay, so should I be concerned about this?

Now, first of all, don’t panic. This isn’t something that happens every day. There’s a good chance it won’t happen to you ever again. In the text you’re about to read, we’ll show what might be the reason behind it. Also, we’ll introduce you to some additional pieces of useful info!

First of all, there’s no need to panic. There’s probably nothing wrong with your vehicle. It’s actually the pump that’s failing to work properly. If this happens to you, contact a station employee ASAP. However, you’ll have to make sure you’ve used the pump in the correct manner. Wait for the nozzle to automatically shut off. 

Needless to say, this teaser ain’t enough! Keep on reading.

Table of Contents

Should a gas pump stop once your tank’s full?

That’s right, a gas pump should stop pumping gas once it “notices” your tank is full. How’s that possible? Well, there’s an interesting mechanism that enables this, and here’s how it works:

  • close to the gas nozzle’s tip is a miniature hole. Also, there’s a mini-pipe that connects the little hole and the handle. When your gas tank’s not full, the air is being sucked into the hole by the vacuum. Therefore, the air will flow “without any hassle”. Now, once the gas in the tank blocks the hole, a mechanism is triggered. The handle senses something’s changed and simply turns the nozzle off.

That’s about it when it comes to the gas pump mechanism. All in all (told in simplest terms): if there’s no airflow, the nozzle shuts off. Don’t believe us? Next time you’re sipping gas, feel free to look for the hole. It’ll be either on the outside or the inside of the tip.

Let’s see another reason why a gas pump might stop. And again, it’s got nothing to do with your vehicle.

Why does the gas pump stop at $75?

The thing is: many gas stations have a $75 limit on certain card transactions (such as Visa or MasterCard). If your tank’s not full once it reaches this limit, then… Yeah, you’ll have to go for a second transaction to finish the process. Talk to your local gas station clerk for more info!

Should I fill my tank all the way up?

Well, it’s a bit hard to say yes or no here. It’s more of an “it depends” type of response (if you catch our drift). Anyway, we’ll show you some pros and cons of a full tank. You’ll be the one to decide!

Here are the pros:

  • You’ll enjoy the less frequent visits to the petrol station. Anyway, when your tank’s half-full, you’ll have to take twice as many trips to the gas station. In case you’re comparing this to when your tank’s full, that is. Some folks might rightly find spending a lot of time sipping gas to be a bit absurd. If you’re one of them, and you value your time, this might be enough to convince you.
  • You’ll enjoy less condensation in your car’s tank. Once the weather turns cold (below zero), water condensation can build up in your gas tank and fuel lines. Here’s how this works. Running your vehicle will cause it to heat up, of course. Once you turn it off, that kind of action will allow the condensation process. If your vehicle’s tank is full, there’s less room for condensation to appear.

And here are some downsides to keeping a full tank:

  • A full tank will result in your vehicle working harder. You’ll be less fuel-efficient by sporting a full tank. However, the money you’ll save won’t make a significant difference. Keeping your tank half-full won’t make a noticeable effect on your gasoline consumption.

So, it’s better to run your vehicle once the tank’s full?

Okay, here’s what experts suggest: you’re better off running your car with a full tank. As you could’ve noticed, that downside isn’t really much of a downside. So, yeah, fill the tank all the way to the top and wait for the nozzle to stop. But, what if it doesn’t happen and the gas pump didn’t stop when full? Is that a reason for concern? Let’s take a closer look!

A person holding a gas pump nozzle.

Gas pump didn’t stop when full – Should I be concerned?

The first thing you’ll want to know is that your vehicle’s probably alright. It’s the pump that’s causing issues. If you were to look at posts on online message boards concerning this topic, you’d… Yup, you’d intuitively think the same. Folks around the world have reported this issue. Regardless of their vehicle’s condition or something, that is.

Anyway, the only thing you should be concerned about might be the gasoline spill. If you’ve spilled some gasoline, you’ll need to clean it. As you know, gasoline’s highly flammable and therefore – dangerous. Also, not all plastic can hold it. If fumes come into contact with a heating source, a catastrophe may ensue.

Say your gas tank has overflowed and you’ve spilled some gasoline on concrete. Here’s how you’ll clean up the mess:

  • First things first, see how you can stop the spill from spreading. Luckily, there’s a good chance you haven’t spilled much. Therefore, you shouldn’t worry too much about this.
  • Next up, you’ll want to use something to soak up the spill. You can try this with trisodium phosphate or just good old baking soda. Let it sit for a while.
  • Once the gasoline clumps up like kitty litter, simply pick it up with a broom. Find a container you’re willing to give up, and throw the clumps into it.
  • Lastly, you’ll want to dispose of the gasoline in a safe manner. See if someone at the pump can help you with this. If that’s not possible, contact your local waste management company.

That should take care of the problem. For more tips on cleaning a gasoline spill from concrete, follow the highlighted link.

What if there’s some gasoline spilled onto the car’s exterior?

Now, there’s a good chance you’ve also spilled some on your car. For handling that spill, you’ll want to use warm water and an ordinary soap combo. Scrub the stain into oblivion! That way, you’ll ensure that there are no further safety risks roaming around your vehicle. The only thing you’ve got left to do is to enjoy a tank full of gasoline!

But, wait, what could be wrong with the gas pump?

So, we’ve already discussed precisely how the mechanism works. Additionally, you’ll want to know that it has a very low failure rate. Even though you’d think this happens a lot, it doesn’t. The number of gas pumps is far superior to the number of issues. Anyway, here are the possible reasons behind their failure:

  • the previous person that has sipped gas had blocked the handle with an object. Trust us, it happens.
  • the nozzle has been damaged in this or that way. Maybe someone angry with gas prices had enough of it.

Now, a pump that’s well-maintained will function for a good amount of time before failing. However, it also comes to whether or not the station’s employees are checking up on it.

Oh, it’s not just the folks from the gas station. Nope. You’ll also have to allow the nozzle to shut itself off by itself. There’s a good chance you’ve witnessed folks trying to fill it up to the brim. Needless to say, that kind of behavior isn’t correct. That’s because it will result in gas flowing into the vapor line that’s designed to handle vapors only. Using the vapor line gasoline will end up inside your EVAP system, wetting it.

What to do in case the gas pump fails?

Let’s say you’ve used the nozzle in the correct manner and it fails. That, of course, results in you trying to manually stop the flow of gasoline. It’s best you call the station manager ASAP and write a report. That’s because a pump that’s failing needs to be serviced.

Of course, you’re not in charge of paying for any spilled gas. It’s their responsibility only; it’s their equipment that’s failed. Keep in mind that all of the things we’ve said above only stand for modern gas stations. The ones that got auto shut-down nozzles, that is.

The bottom line

Alright, so that should conclude our today’s article on the gas-pump-didn’t-stop-when-full issue. Hopefully, now you know that this shouldn’t signal the end of the world. Most probably, there’s nothing wrong with your car. It’s the fuel pump that’s failing. Just call up the station clerk and see what’s there to be done.

For more interesting tips on gasoline, gasoline pumps & prices, click right here.