Diesel car owners in the country have been urged to stay vigilant, as rising reports of adulterated and contaminated diesel continue to put engines at serious risk. Detecting bad fuel early could save motorists thousands of rands in repair costs—making awareness more important than ever.
Understanding the Risks of Adulterated and Contaminated Diesel
Two main fuel-related threats are currently affecting diesel users: adulteration and contamination. While they sound similar, they come from very different sources and cause unique problems.
- Adulterated diesel is fuel that has been illegally mixed with paraffin—a cheaper substance used to stretch fuel quantities while increasing profit margins for criminals. This altered fuel is then sold to unsuspecting filling stations as if it were legitimate diesel.
- Contaminated diesel, on the other hand, refers to fuel that has been tainted with physical impurities like dust, rust, or microbial growth—usually due to poor storage or transport conditions. Both of these fuel types can significantly impact engine performance.
How These Fuels Damage Your Car
Using diesel that has been tampered with can quietly damage your engine over time. In the short term, the most common problem is fuel filter blockages. If you find yourself needing to change filters more frequently than usual, it may be a sign that you’re using dirty diesel.
Adulterated diesel is trickier to spot immediately. However, one major red flag is engine malfunction caused by faulty or deteriorating fuel injectors. These parts are highly sensitive to impurities, and once compromised, they can ruin the engine’s fuel spray pattern, leading to combustion issues.
Over time, this degradation can escalate into full-scale engine damage. Key warning signs to look out for include:
- Trouble starting the engine
- Increased engine noise
- Weakened acceleration
- Unexpected smoke emissions
- Higher-than-normal fuel consumption
- Sluggish performance
- Gearbox strain or more frequent gear changes
- Irregular engine idling
These symptoms should not be ignored, especially if they appear together. While they aren’t exclusive to bad fuel, they do strongly indicate something is wrong.
Adulterated Diesel on the Rise in the Country
The issue has caught the attention of national authorities. In a 2022 parliamentary debate, Mineral Resources and Energy Minister Gwede Mantashe acknowledged the growing presence of adulterated diesel in local markets.
That warning became reality in January 2024, when a national probe found that 7% of fuel stations were selling compromised diesel—a total of 70 out of 1,000 outlets tested.
South African Revenue Service (SARS), working alongside the National Joint Operational and Intelligence Structure (NATJOINTS), has since seized over two million litres of adulterated diesel in various sting operations.
But the scale of the problem remains daunting. Paraffin sales—used in fuel adulteration—have surged dramatically, reaching 1.2 billion litres in December 2024, up from 600 million litres just five years earlier.
Can the Fuel Supply Chain Be Cleaned Up?
Experts believe a targeted approach could reduce adulteration. One of the most talked-about ideas is adjusting the tax structure on paraffin. By increasing its tax to match diesel, the incentive for criminals to dilute diesel with paraffin may be removed, thereby undercutting their profits.
However, these changes are yet to be implemented. Until then, drivers across the country will need to stay alert to avoid falling victim to contaminated or adulterated fuel.
Drive Smart, Stay Safe
With no immediate regulatory fix in sight, the best defence is awareness. If you notice any unusual engine behaviour, get your fuel system checked immediately. Avoid unknown or questionable fuel stations, and if possible, stick to major retailers with proven quality control.
Your vehicle’s performance—and your wallet—depend on it.
Related article: PetroSA’s R11 Billion ‘Contaminated’ Petrol Debacle: The Fallout from Nako Energy’s Adulterated Fuel
