Once that low fuel warning light comes up on the dashboard, the most common question that comes to mind is it bad to run your gas tank empty?
To be honest, a significant amount of drivers practice this sort of driving. It might be from necessity, it might just happen from time to time or it might be just a bad habit.
This article will try and explain the whole matter. If you’re not up for reading, you have a video at the end of the article that you can also watch on our YouTube channel.
WHAT HAPPENS WHEN YOUR GAS TANK IS EMPTY?
To clarify before we start, driving on an empty gas tank, of course, isn’t possible.
By driving on empty people usually mean driving on leftover fuel in the gas tank, the so-called reserve fuel level.
This is the backup measure that car manufacturers made to assure that you have some more travel distance leftover before the gas tank really becomes empty.
A system mainly made to so save you from being left out of gas in the middle of driving.
When the gas tank does become empty, the usual scenario is that the car briefly stutters (like from a misfire for instance) and then the engine completely shuts down. The dashboard warning lights come up and the car starts losing power steering, power brakes, and other vital systems.
Luckily, most car manufacturers have redundant systems that enable you to safely pull over and stop the car which you should do immediately.
IS IT BAD TO RUN YOUR GAS TANK EMPTY?
The simple answer is yes. Not that it’s bad in the sense that it will damage your car permanently (in most cases). It’s just that you may have consequences that are sometimes serious, costly, and time-consuming.
Here are some of the main reasons you should avoid driving on an empty tank:
1. FUEL PUMP PROBLEMS
This is by far the most important reason when talking about is it bad to run your gas tank empty.
You see, modern fuel injection systems depend on high and stable fuel pressure. The fuel pump is in charge of providing that.
In the majority of cars, the fuel pump is located inside the gas tank, usually near the bottom. One of the reasons why this is done is so the fuel can be used as both a coolant and a lubricating medium for the pump.
So, once the gas tank is empty, the fuel pump essentially runs out of coolant and lubricant and suffers damage in form of overheating or a breakdown.
Luckily, most of these pumps have a sturdy and resilient build so they can take a couple of empty gas tanks without damage.
But if you make a habit of driving empty, this problem will happen for sure.
The solution is a fuel pump replacement. In most cases it’s costly and time-consuming, all depending on the location of the fuel pump. In some cases, you may even have to take off the gas tank.
More about fuel pump problems in an article that you can read by clicking here.
Also, you can read about how to solve a fuel pump problem by clicking here.
2. CLOGGED FUEL FILTER
Over time, a layer of filth might gather at the bottom of the gas tank.
This is especially present if you have an older, high-mileage car that has spent lots of gas tanks of fuel.
Also, if the fuel quality in your country is poor, this is almost inevitable.
Over time, the debris settles at the bottom of the gas tank and doesn’t cause any problems if you drive the majority of the time on a full or half-full tank.
But when the gas level comes to the bottom, the debris starts mixing with the gas and gets sucked into the fuel system.
The debris gets caught inside the fuel filter. If there’s some serious debris and filth, the filter may get clogged.
Once this happens, the fuel flow will stop and the engine will stutter and cut off due to lack of fuel.
Solving the problem isn’t that complicated and involves replacing or more rarely cleaning the fuel filter.
Changing a fuel filter is not that much of a problem and doesn’t cost that much, the main problem may be accessibility.
3. AIR GETS INTO THE FUEL SYSTEM
Fuel systems on today’s cars, as mentioned, are pressurized. When the gas tank runs empty, instead of fuel, air get’s into the system (fuel filter, fuel lines, and else).
This can create a sort of vacuum that can prevent the car from starting. Even after adding fuel, it will crank but won’t start.
Diesel cars are especially sensitive to this problem. Besides this, heavy cranking can totally deplete the car battery and cause an additional problem.
Some cars have systems to prevent this, but at least from my own experience, no car will start immediately after pouring gas like it does when the situation is normal.
It takes some serious cranking (or even towing in more severe cases) to start the car.
4. RISK OF THE CAR STOPPING AT ANY MOMENT
Know that when you’re driving on a near-empty gas tank, you’re at risk of the car stopping at any moment.
Luckily car manufacturers have made several precautions to avoid this. First is the fuel gauge, then the low fuel warning light accompanied with a sound signal, and then the possibility to check your leftover range on the board computer.
All of this is to prevent the car from running out of gas, mainly during driving. This is immensely important. Just imagine what would happen if the engine shuts down during an overtaking for instance, or in high-speed driving.
In these cases, it’s also good to know the fuel consumption of your car so you can better calculate how much driving you have left.
We’ve written a separate article on this specific topic, click on the link if you want to see it.
5. PSYCHOLOGICAL EFFECT
When talking about is it bad to run your gas tank empty, this reason seldom comes to mind but is very important nevertheless.
Driving on an empty gas tank may create a sense of anxiety in drivers, especially the more inexperienced ones.
When will the car stop, how far can I go, and is there a gas station nearby are just some of the questions.
This then usually results in loss of concentration and distraction while driving which is outright dangerous.
HOW LONG CAN YOU DRIVE ON AN EMPTY GAS TANK?
The answer to this question lies in the capacity of your car’s fuel tank and, more importantly, its fuel reserve.
As mentioned, the fuel reserve is the amount of fuel left once the warning light comes up.
On average, it’s about 10 percent of the total gas tank capacity or more.
So, for instance, on my Skoda Fabia, the gas tank capacity is 45 liters while the reserve fuel holds 7 liters which is about 16 percent.
At an average consumption of 7 liters per 100 kilometers, I have about 100 kilometers before the engine cuts off.
That is without forced driving and without a lead foot on the gas pedal which I wouldn’t recommend anyway. Saving some gas may mean the difference between reaching the next gas station and having a long walk with a gas can.
If you want to read more about how to save fuel, click here for a separate article on that topic.
So, it all boils down to knowing the data. Try remembering the capacity of your gas tank, what’s the reserve fuel level, and the fuel consumption of your car.
Of course, besides that, you have the board computer but know there might be some discrepancy in the numbers. If you’re going for the last drop of fuel, be aware.
All of this combined with some attention should prevent you from being left out of gas which is the most important thing.
Hopefully, you’ll agree by now what’s the answer to the question is it bad to run your gas tank empty.
By far, the best thing to do is to avoid driving with an empty or near-empty tank.
Simply, the trouble caused by this problem far outweighs the simple task of watching the fuel gauge and having some common sense.
Getting stranded on the side of the road, sometimes helpless, and begging around for help is a big price to pay for not visiting a gas station on time.
Besides this, if you persist in driving this way, you can probably expect some car repairs in the near future.
As a final recommendation and if possible, try to have at least half a gas tank full at all times.
This will perhaps save you from unnecessary problems. Not to mention the fact that the car is always travel-worthy so to say.
You never know what the situation will be and it’s always better to be safe than sorry.
Written by: Sibin Spasojevic
Former car technician, life-long car and DIY enthusiast, author for Despairrepair.com
IS IT BAD TO RUN YOUR GAS TANK EMPTY? YOUTUBE VIDEO