How contaminated diesel can cause ‘catastrophic’ failure in your car’s engine

Toyota South Africa Motors (TSAM) has expressed its concern over the shock revelation that local motorists have been unknowingly exposed to contaminated diesel.

The Department for Mineral Resources and Energy found that 70 filling stations around the country were selling diesel mixed with illuminated paraffin. As paraffin is cheaper than diesel, such a practice will see wholesalers make more profit as they will still sell the final product at the same price as uncontaminated diesel.

Diesel issue sends wrong message

Andrew Kirby, president and CEO of TSAM, said that the consequences of the revelation stretches much further than the actual damage diesel engines will suffer in the long run.

“I’m more concerned about the message and the lack of being able to control fuel quality in South Africa and what that could mean for us in the future,” Kirby said during TSAM’s annual State of the Motor Industry address at Kyalami this week.

“We are pushing very hard for more advanced engines using a lower sulphur grade of diesel. This type of controversy doesn’t help us.

“We need to demonstrate that we are using low PPM fuel in order to utilise Euro 6 and 7 grade engines. We still have Euro 3 in South Africa. If we are going to be making the transition to lower emission and emission-free vehicles, we need to achieve that with our fuel quality as well.”

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Sensitive matter

Kirby assured Toyota customers that the manufacturer will deal with the issue sensitively and “walk the journey” with them.

“We don’t know how many times people filled up with these fuels and the distances they drove, as it will have a big impact on the life span of these engines.

“We don’t have any direct concerns at the moment, but we’ll obviously be watching it very carefully when customers do come in with any problems.”

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Contaminated diesel affects lubrication

TSAM provided The Citizen Motoring with a detailed technical explanation of why it is detrimental for a diesel engine to run on contaminated fuel.

“Paraffin affects the lubricity of the fuel and does not contain any of the necessary additives required by modern engines. These additives assist with the lubrication and cleaning of the moving parts in the diesel injection system and the conditioning of the seals,” Toyota said.

“These components will fail with the repeated use of paraffin. Furthermore, the flashpoint of paraffin is lower than diesel which could lead to engine knock, which can cause catastrophic engine failure.”

The carmaker added that the potential damage suffered by a diesel mill will be determined by the amount of contaminated fuel that was used and the mileage covered.

Depending on the quantity of the percentage of the paraffin in the diesel, it is likely that the use of contaminated fuel will not be apparent immediately. But tell-tale signs would be exhaust gas odour and engine knocking.

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Impact on warranty

Further bad news for motorists is that a vehicle’s manufacturer’s warranty will likely not cover any damage caused by contaminated fuel.

“The engine and fuel systems have not been designed to run on paraffin. Its use will affect the manufacturer’s warranty should there be any consequential damage from the contaminated fuel.”

Toyota’s best advice for any motorist suspecting the presence of contaminated diesel is to have the tank drained and filling it up with clean diesel and add injector cleaner. Services at recommended intervals are also highly advisable.