You’ve probably been told at some point in your driving career to not drive your car while the gas tank is on empty, but did you know why that is? This recommendation is more than just an old wives’ tale—you can damage your car by ignoring that gas light for too long.
First, you should understand what your fuel light indicator really means. When you hear the familiar “ding” that accompanies your fuel light, your fuel tank has reached “reserve” levels, or around 10-15% capacity. It is possible to calculate how long that will last using your car’s average range, but we would advise against it, just to be safe. Avoid doing the math if you know you are the type of person to risk it and drive on empty anyway.
One reason it’s not advisable to drive on an empty tank is the potential damage to your fuel pump. The fuel pump is responsible for transporting gasoline from the tank to the engine, and it depends on that same gasoline to stay lubricated and avoid overheating. Overheating any part in your vehicle is never a good thing—fuel pump included. Running on a low gas tank can cause overheating of the fuel pump and premature failure. Replacing your fuel pump is a costly and preventable repair.
Another part you risk damaging is your fuel filter, which keeps harmful sediments and dirt from getting into your engine. Naturally, sediments sink to the bottom of your fuel tank, so running on empty means your filter could be getting clogged with dirty fuel. Your fuel filter may even become completely blocked in some cases.
The most obvious risk you take when ignoring your fuel light is, of course, running out of fuel. Not only is getting stranded embarrassing, but it can also be dangerous in severe weather and costly when you end up needing a tow to the nearest gas station.
So, while it may be tempting to wait until a more convenient time when your fuel light comes on, you should do your car a favor and fill up as soon as possible.