The reserve light comes on on your dashboard. Don't panic! Contrary to popular belief, you generally have a comfortable margin of maneuver before running out of fuel. Find out the truth about the remaining range and the precautions to take to preserve your vehicle.
Variable autonomy depending on the model
The moment the fuel light comes on can be a bit of a stressful time for drivers. However, there is no need to panic right away. The remaining range depends on several factors specific to each vehicle.
Pierre Dupont, an automotive expert at a major French manufacturer, explains: “As a general rule, the light comes on when there is between 10% and 15% of the total capacity of the tank remaining. This represents a comfortable safety margin for most urban journeys.”
Estimate your real autonomy
To accurately calculate remaining range, two key elements come into play:
Tank capacity: This varies considerably from model to model. A city car might have a 40-litre tank, while a large SUV might have 80 litres or more.
Average consumption: It depends on the type of engine, driving style and traffic conditions. A petrol vehicle in the city will consume more than a diesel on the motorway.
Marie Leroy, an automotive engineer, explains: โFor a quick estimate, multiply the remaining capacity of your tank by 100 and divide by your average consumption. For example, with 4 liters remaining and a consumption of 6 L/100 km, you can theoretically travel around 66 km.โ
Figures to be qualified
Although these calculations give an indication, it is crucial to remain cautious. Jean-Michel Martin, eco-driving trainer, warns: โThese estimates are based on ideal conditions. In reality, many factors can reduce autonomy: heavy traffic, sporty driving, use of air conditioning, etc.โ
It is therefore recommended to consider these figures as a maximum limit and to provide a safety margin. In practice, we can retain these orders of magnitude:
The risks of prolonged driving in reserve
Although technically possible, systematically driving with an almost empty tank is not without consequences. Sophie Dubois, a mechanic specializing in the maintenance of injection systems, warns of two major risks:
Fuel system damage: “The bottom of the tank accumulates impurities. Drawing from this area can cause premature clogging of the fuel filter or even damage to the fuel pump.”
Premature pump wear: โWhen the level is very low, the pump can suck in air. This causes overheating and mechanical stress which reduces its life.โ
Adopting good practices
To preserve your vehicle and avoid stressful situations, here are some wise tips:
Plan your fill-ups: Plan a stop at the gas station as soon as the level reaches a quarter of the tank. This will avoid stress and preserve your engine.
Keep an emergency reserve: An approved 5-litre jerrycan in the boot can get you out of a sticky situation, especially on motorways where petrol stations are far apart.
Adopt eco-driving: Smooth and anticipatory driving can reduce your consumption by 15 to 20%, thereby increasing your autonomy.
Use apps: Many mobile apps locate the nearest gas stations and compare prices, allowing you to optimize your stops.
The reserve light should not be a source of anxiety, but rather a benevolent reminder that it is time to think about filling up. By understanding how your vehicle works and adopting the right reflexes, you will drive with complete peace of mind, even when the needle flirts with zero.