Drivers stranded as dodgy diesel stops engines

Thousands of motorists could be left stranded this winter due to poor quality diesel clogging up their cars’ fuel filters, the RAC has warned.

The recovery operator reported a six-fold increase in the number of call-outs to drivers whose cars had ground to a halt. In November alone, the RAC said its patrols attended 600 incidents – the usual is around 100 – where diesel cars either wouldn’t start or had lost power. It estimated that a further 1900 people could have experienced similar problems.

Although the exact cause of the problem is not yet known, experts have suggested they could be a result of increased levels of biofuel in diesel. All diesel sold in the UK has up to 7% biofuel content, which has a tendency to solidify, or ‘wax’ in cold temperatures.

When this happens, the waxy deposits clog up the fuel filter and starve the engine of fuel, resulting in a loss of power or failure to start at all. The amber engine malfunction light might also come on.

However, the RAC said the symptoms of the current problem, while similar to those experienced during normal waxing, are different and could suggest another cause. Normally when temperatures rise, any wax deposits dissolve back into the fuel. In this case, that hasn’t happened and fuel filters have had to be replaced.

RAC technical director David Bizley said the organisation is working with fuel suppliers and car makers to identify the exact cause of the problem. He added that the fuel in question was not specific to any retailer or type of retailer but that the issue appeared to be more prevalent in eastern parts of England and Scotland, with the greatest concentration of breakdowns occurring in the North East.

'The industry is working extremely hard to find a solution, which is good news for motorists. Neither the fuel producers, nor retailers, nor the motor manufacturers saw this problem coming last year. The current specifications for all fuel sold at the pump have been developed over many years and continue to evolve based on a combination of test programmes and field experience.’

Fuel industry representative body UKPIA said it is investigating. In a statement it said: ‘The parameters of investigative tests, at this stage, are all encompassing, including quality of biodiesel, base hydrocarbon fuel, how the product is blended and any other additives used.’