What Happens If You Run Out of Fuel — and How to Avoid It

Running out of fuel happens to more drivers than you'd expect — the AA alone deals with over 800,000 fuel-related callouts per year. Here's what to know.

What Happens to the Car

When the fuel tank runs completely dry, several things happen:

Petrol engines: The fuel pump is lubricated and cooled by the fuel surrounding it. Running the pump dry can cause it to overheat and fail. Fuel pump replacement typically costs £200–£600.

Diesel engines: Running dry introduces air into the fuel system. The system must be bled (purged of air) before the engine will restart — a job that often requires a mechanic rather than simply adding fuel.

Catalytic converters: In petrol cars, unburned fuel entering a hot catalytic converter can damage or destroy it. A replacement catalytic converter can cost £300–£1,500.

What To Do

1. Signal and coast to the left — use your remaining momentum to reach the safest possible stopping point

2. Hazard lights on immediately

3. Do not repeatedly crank the starter — this runs the fuel pump dry faster and risks damage

4. Call for roadside assistance — a technician will bring fuel and, in the case of a diesel, bleed the system

The Reserve Light

Modern cars typically show a low fuel warning at 10–15% remaining, giving you roughly 30–50 miles of range. But 'fuel range' estimates on dashboards are calculated from recent driving — motorway driving suddenly switching to urban stop-start will deplete that reserve faster than predicted.

A Note on Diesel Contamination

If you accidentally fill a diesel car with petrol (or vice versa), do not start the engine. Call immediately for misfuelling recovery — starting the engine causes the contaminated fuel to circulate and damage is rapid and expensive.

Run out of fuel near Newport, Cardiff, Bristol or Bath? Fred's Towing Services provides fuel delivery and roadside assistance 24/7. Call 01633 982028.