What happens when your car runs out of petrol while driving?

Many of us have gone into a petrol station with some kilometres left on the tank, but what happens when you run out of petrol while driving?

It’s always risky when gambling how far you can go with the low fuel light on, even more so when you’re driving through rural Australia hoping to make it to the next town.

If you do lose to the low fuel light, it may be a long walk or a long wait until someone comes to assist you.

What happens when you run out of petrol?

When your car runs out of petrol, it won’t just stop, like in the movies. It will show warning signs including the engine sputtering and coughing, intermittent power surges and possible engine backfires.

Running out of fuel is not great for your car, but even running extremely low isn’t good either for a lot of reasons. The car’s fuel pump uses petrol as a means of lubrication or cooling and can be damaged when there’s nothing in the tank.

The fuel pump will use the last dregs from the bottom of the tank, which is where sediment and debris settle. You could end up with only a clogged fuel filter or you could damage the pump or clog the fuel injectors. Debris from the damaged fuel pump could get into your car’s fuel system and air could get sucked into the fuel lines.

You could be in more trouble if your brakes and steering rely on hydraulic assistance, which will die when the engine cuts out. You’ll have to work harder to turn the wheel and apply the brakes.

If you drive a diesel car, running out of fuel is even more of a concern as high-pressure direct injection doesn’t tolerate air in the system. The whole system will have to be primed to remove all traces of air. You will also run the risk of damaging the diesel injection pump and fuel injectors.

What do you do when you run out of fuel?

 If you missed all the warning signs and are running extremely low or are out of fuel the best thing to do before the tank runs dry is to move your car safely away from traffic and switch on your hazard lights. This will decrease the chance of damaging the car and increase the chance that the engine will start again when you pour more petrol into the tank.

If you’re close to a petrol station you, or someone else, can walk there, buy a jerry can, fill it with petrol and walk back to the car. Assuming you don’t have a clogged fuel filter or injectors then you should be able to start the car and be on your way. Otherwise, if it doesn’t start you may have to get your vehicle towed to a mechanic.

If you are in an unfamiliar area or remote with no signs of a service station, you should stay with your car and seek roadside assistance. Even if you’re not a member, some roadside assistance services can do call-outs usually for a fee. If your car is new and depending on the brand, you might have roadside assistance as a part of your ownership package.

Your car has the instruments needed to avoid a mistake that can be costly. As a bare minimum, you’ll have a fuel gauge with a low-fuel warning light, and newer cars will come with a trip computer with a distance-to-empty function.