We often take for granted just how complex and dangerous cars are. Everything has to be in its place and running correctly to avoid serious risk of accident and passenger injury.
Pumping gas may be a very simple task, but if nobody taught you how to do it and what to be aware of, you could cause a disaster.
From a mechanical standpoint, there’s no problem with pumping gas while the car is running, but you should avoid doing it at all costs. Gasoline is extremely flammable and can be ignited by the smallest catalyst, so you should minimize the risks involved.
Before we get into proper safety precautions when pumping gas, let’s review its chemical properties and why it’s such a volatile liquid.
In its liquid form, gasoline is very hard to ignite – it requires over 247° Celsius to ignite without being ignited by a catalyst.
However, the flashpoint is much more important – it’s the point where liquid releases enough vapors to ignite in the air. Gasoline has a flashpoint of -23° Celsius, which means that even if it’s freezing cold outside, a match or a single spark can still ignite gasoline without a problem.
Effectively, gasoline is always emitting highly flammable vapors that are heavier than air so they stick around any open canister, and especially around gas stations. It’s also hardly visible and can travel great distances from its source.
Diesel on the other hand has a flashpoint of 55° Celsius, which makes it a lot safer. Still, it too can ignite, especially on a hot summer day.
When you stop at any gas station, you’ll see several very obvious signs telling you to turn the engine off and avoid any sources of flame, including smoking.
The sources of open flame are extremely risky and near-guarantee of gasoline ignition. By opening the gas tank and placing the nozzle inside, you’re allowing the gasses to escape and get pushed out as the tank is filled with more liquid.
You can find hundreds of videos online where people cause fires at the gas pump, and here’s just one example.
The reality is that leaving the car running is not nearly as dangerous as an open flame, but considering that hundreds, if not thousands of cars pass through the gas station every day, it takes only one car to start a fire.
You’re far more likely to cause a fire by creating a static buildup on your clothes and discharging it near the fuel tank. However, no matter how small the risks are, you should still turn the vehicle off.
The bottom line is that leaving your vehicle running is a public hazard and illegal almost everywhere in the world. You may not cause an accident, but you’ll certainly get into trouble.
But what about pumping gas at home? Again, it’s bad practice to leave the engine running, even if the risks are fairly low. The only reason why I’d consider pumping gas while the car is running is if I had a bad starter, as turning the engine off would leave me stranded.
This step-by-step guide will help new drivers, teenagers, and those that always had the gas station worker pump their gas for them to learn how to do it. Even though it’s a simple process, it’s always good to review the basics.
If you need to refuel from a canister and you don’t have a funnel, you can use a 1-2L plastic bottle instead. Wash out the soda and shake out the water, then take a knife and cut a slanted section towards the rear of the bottle.
Place it in the fuel tank, and it will act as a makeshift funnel – just make sure it’s properly seated and is pressing on the safety latch that’s keeping the fumes from escaping.
You can’t know the exact amount of gas your vehicle can take, because you have to take into account the fuel that’s already inside the tank, as well as the slight difference between gas tank capacity and total capacity which includes the fuel line.
However, if you’re pumping at a gas station, there’s nothing to worry about. The nozzle is capable of detecting when the gas tank is full and will stop automatically. If you’re filling up at home, estimate the amount of fuel left in the tank, then subtract it from the tank capacity. That’ll give you a rough idea of how much fuel you can put in.
Pumping gas with the engine running is illegal in all 50 states. The safety risks may be minimal, but the law is clear and you should always turn off the car before refueling.
It’s a good idea to touch the car before starting to pump gas to discharge static electricity that may have accumulated in your body. However, you’re already doing this by closing the driver’s door and opening the metal fuel tank lid, so you don’t have to worry about it.
This depends entirely on the rules set by the gas station company. As far as safety risks go, there’s virtually no chance of causing a fire by using your phone.
You should never leave a running fuel nozzle unattended as that is extremely dangerous. By engaging the latch, the nozzle will keep the fuel flowing until the gas tank is full. However, if it falls out and the impact doesn’t disengage the latch, the nozzle will spread fuel around uncontrollably until someone manually shuts it off.
The consequences of pulling out the gas hose can be severe. Modern systems have a built-in safety latch where the hose disconnects to prevent further damage and a fire hazard, but if it’s an older system, tugging on the metal terminal will cause a spark which will set off a massive fire.
A good practice is to always check your mirrors for the fuel line before driving off from the gas station.
Gasoline becomes denser as the temperature drops, but the difference in the amount of gas gained will be marginal. This rule is more applicable to propane, butane, and other flammable gasses.
Now that you know why you should turn off the car while pumping gas, I hope you turn off the engine every single time. Even though it doesn’t pose much of a risk, the law is very clear and you should avoid unnecessary fines.
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