Contaminated diesel warning for South Africa – What to look out for

Learning how to detect and avoid adulterated or contaminated diesel is essential for maintaining your car’s engine health.

Adulterated diesel refers to fuel that has been blended with paraffin before being sold to fuel stations as legitimate.

This allows criminals to sell twice the amount of fuel with high profit margins, thanks to paraffin being substantially cheaper than diesel.

Contaminated diesel, on the other hand, is fuel laced with particles such as dust, rust, or microbes.

Adulterated and contaminated diesel poses a risk to your vehicle’s engine, leading to less efficient running at best or serious damage at worst.

There are, however, ways to detect if you’re currently using problematic diesel, with certain signs and engine symptoms being clear indicators.

This includes simple things like an issue with fuel filters frequently becoming clogged, which may indicate the presence of solid matter contaminants in the diesel.

For adulterated diesel, detecting the signs is more difficult, but not impossible if you’re paying attention to your vehicle’s performance.

A key indicator is engine malfunctions caused by partial fuel injector failures.

Fuel injectors are designed and manufactured within precise operational parameters, and prolonged exposure to impure fuel or contaminants will degrade their internal metal surfaces.

When an engine’s fuel injectors begin to fail due to this degradation, the fuel spray pattern within the combustion chamber will be disrupted.

This can then develop into a cascade of internal damage, eventually resulting in complete engine failure.

Below are some of the symptoms of a damaged or misbehaving fuel injector:

• Difficulty starting the engine
• Unusual engine noise
• Reduced engine power
• Smoke
• Increased fuel consumption
• Extended cycle times or reduced speed
• Frequent use of lower gears
• Rough idling

While not all of these are unique to fuel injector issues, keeping an eye out for such problems and responding accordingly when they appear will make it easy to keep your car in good running condition.

Adulterated diesel in South Africa

In a 2022 parliamentary sitting, Mineral Resources and Energy Minister Gwede Mantashe commented that adulterated diesel was becoming more common at petrol stations.

An investigation in January 2024 confirmed this concern, finding that out of 1,000 fuel stations, 70 were selling adulterated fuel.

Additionally, SARS recently reported that while working with the National Joint Operational and Intelligence Structure (NATJOINTS), a series of operations had successfully seized two million litres of adulterated diesel.

While this is good news, it speaks to the size of the adulterated fuel market, as seen by the rapid increase in paraffin sales.

In December 2024, paraffin sales had reached 1.2 billion litres, coming from only 600 million litres in 2019.

One of the main advocated solutions for this nationwide issue is to hit the adulterated fuel market in its supply chains.

This can be achieved by adjusting paraffin taxation to bring it more in line with diesel and undercut the criminals’ profits.

Besides the recent success of SARS, no solution has been implemented yet, so South African diesel car drivers must remain alert.