How long can you drive with an "empty fuel tank"?

The photo is taken from the site: http://lotow.com.au/index.php/fuel-delivery/

When operating the car, drivers face with such a situation, when there is a minimum of fuel left in the gas tank, a light warning of a petrol shortage shows up, while there is still a few dozen kilometers before refueling. How much can you drive on a half-empty fuel tank and whether such operation is dangerous?

How to calculate the approximate mileage?

Most drivers try to prevent such situations when the fuel shortage light shows up. Moreover, today it will be simply dangerous for a car engine to refuel at the unknown petrol station. Many car owners choose a specific brand of petrol stations in their city, which has the quality fuel. As a result, if the light shows up, we urgently need to go to the gas station, and it’s not a fact that the quality of the fuel there will be at a good level.       

The photo is taken from the site: https://www.thestreet.com/amp/story/13161703/1/gasoline-prices-to-tick-upwards-as-summer-demand-increases.html

In each case, the mileage will vary when the light flashes on. It is necessary to take into account the speed limit, the use of a car in a city in traffic jams or on a highway outside the city, the volume of the tank and the total fuel consumption. On average, passenger cars signaling a shortage of fuel can travel about 30 miles. But crossovers and SUVs, with an increased volume of the fuel tank, can travel with a burning light 40-60 miles. 

Many modern cars are equipped with an extremely useful function, which calculates the volume of petrol available in a tank, current fuel consumption is also taken into account, after which the system gives the current mileage on the dashboard until the tank is completely empty. This will allow you to plan your trips as accurately as possible, while the car owner will be completely sure that he will not get in the middle of the road with the fuel ran out. Today, many cars are equipped with such extremely useful and fairly simple functions, so it would not be superfluous to get acquainted with the operating instructions of your vehicle, and you may well find a way to activate this option and constantly get the necessary information about the mileage until the tank is completely empty.

However, it is necessary to understand that in these cases, when there are numerous contaminants at the bottom of the tank, the sensors do not ensure the quality of measurements, the indicators on the dashboard may not be accurate enough, so the system will show that there is still fuel in the tank, while the car will consume last liters of petrol or diesel. Therefore, the car owner needs to calculate everything for a specific mileage, as well as test the fuel tank every six months, filling it under the throat, which will check the accuracy of the readings of the built-in fuel volume sensors.

Is it dangerous to drive with an “empty fuel tank”?

Car owners often wonder if it is safe to drive a car with a minimum level of fuel. It is necessary to note that the harm of such exploitation will largely depend on how often you have to operate vehicles with a minimum level of fuel. If you constantly refuel with gasoline, but once on the highway or in the city there was such an alarm, then of course there will be no harm to the car. But if this is constantly noted, then the fuel pump, filter and engine may experience certain problems.

The fact is that the fuel pump, which provides for the injection of pressure in the system, is located in the fuel tank, cooled and lubricated by the fuel in which it is immersed. If a minimum of fuel remains in the tank, then the pump, although it pumps fuel, may still be heated while working dry, which ultimately leads to the failure of this expensive element. As a result, the car owner will expect costly repairs, which in most cases include the pump replacement.

Also, when operating vehicles with a minimum fuel level, the pump can pump the fuel from the very bottom of the tank, where water, heavy fractions and dirt are usually accumulated. As a result, all this enters the system, clogs the injectors and can completely disable the engine of the car.