Most South African motorists have done it at least once, watching the fuel gauge creep toward empty while hoping the next petrol station isn't too far away. With petrol prices having risen almost every month, the temptation to stretch every drop is understandable. But automotive experts warn that making a habit of running on an empty, or near-empty, tank could cost you far more in repairs than you'd ever save at the pump.
Related: June 2026 Fuel Price South Africa Update: Relief for Diesel, But Petrol Taxes Sting
What happens inside your engine
The damage caused by a chronically low fuel tank is largely invisible until it's too late. Here's what mechanics and automotive engineers say is happening under the bonnet:
1. Your fuel pump overheats
In virtually all modern vehicles, the electric fuel pump sits submerged inside the fuel tank and relies on the surrounding fuel to keep it cool and lubricated. When fuel levels drop too low, the pump is exposed to air, a poor conductor of heat, causing it to run significantly hotter than designed. Over time, this sustained overheating could wear down the pump's internal components and can lead to premature failure.
2. Sediment gets sucked into your engine
Over time, fuel tanks accumulate rust, debris, and contaminants at the bottom, particularly in older vehicles. When your tank is nearly empty, the fuel pump might begin drawing from this contaminated layer. That sediment can clog your fuel filter and, in worst cases, reach your fuel injectors, causing rough idling, hesitation, engine misfires, and poor performance.
3. Catalytic converter damage
Sustained fuel starvation can cause engine misfires, pushing unburned fuel into the exhaust system. This can overheat and permanently damage your catalytic converter, one of the more expensive components to replace on a modern vehicle.
The real cost of ignoring the warning light
In South Africa, replacing a fuel pump can cost between R1 500 and R7 000, depending on your vehicle's make and model. That figure includes labour costs of R500 to R1 500 and a replacement pump ranging from R1 000 to R5 000+, a bill that can easily be avoided by simply keeping your tank topped up.
Practical tips for South African motorists
Given South Africa's unique challenges, from long distances between rural fuel stations to the fuel stations considering closing in the evenings to bring costs down, the following habits are strongly recommended:
- Follow the quarter-tank rule: Never let your fuel drop below a quarter of a tank. Treat it as your new empty.
- Act on the warning light immediately: The low-fuel light is not a range estimate; it's an emergency signal. Pull in at the next available filling station.
- Plan your route: The Automobile Association (AA) of South Africa advises motorists to identify fuel stops before long trips, particularly in rural or semi-rural areas.
- Keep up with servicing: A regularly serviced vehicle with clean fuel filters is more resilient to occasional low-fuel events.
- Join a roadside assistance programme: If you do run dry, the AA's emergency fuel delivery service can get you moving again safely without risking further vehicle damage.
The bottom line
Running your car on empty might feel like a small risk in the moment, but the cumulative damage to your fuel pump, injectors, and catalytic converter can result in repair bills that sting far harder than a full tank of petrol ever would. In a country where fuel costs are already a major household expense, protecting your vehicle's fuel system is simply smart financial management.
