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Fuel filters blocked on diesel cars due to cold weather, says RAC

RAC patrols attended almost 500 diesel vehicles of varying makes and ages after their fuel filters became clogged on Friday (March 2).

The issue represented a significant 5% of the 9,600 breakdowns the RAC dealt with on a day that saw 44% more call-outs than there should have been for the time of year.

Filters appear to have become blocked due to the formation of a gel-like substance in the diesel that leads to the engine being starved of fuel and either not starting or losing power. The amber engine malfunction indicator light might also show.

The cost of a garage replacing a clogged diesel fuel filter could be as high as £200 depending on the vehicle, says the RAC.

RAC fuel spokesman Simon Williams said: “The RAC last saw issues with diesel ‘waxing’, as it is known, predominantly in the east of the UK in the very cold weather of late 2013, and to a lesser extent in periods of really cold weather since then.”

Williams told Fleet News that his should not occur as all diesel produced for UK winter use is formulated with additives to prevent waxing.

“In addition, modern diesel vehicles are fitted with heating elements on the fuel delivery lines to prevent waxing occurring,” he said

“We are, however, aware that some vehicles’ fuel lines are more exposed than others which can exacerbate waxing issues.”

The problems seen in late 2013 led to a working group being set up to investigate the cause.

The RAC is an active participant along with other breakdown service providers, motor manufacturers and representatives from the fuel industry.

“Frustratingly for motorists, however, there is still no solution to this problem,” continued Williams. “The most likely explanation appears to be that there are a combination of factors at play involving the diesel itself, its bio content, and the way vehicles move the fuel around their systems.

“Unfortunately there is nothing diesel car drivers can do to prevent the problem from occurring other than getting their vehicles’ fuel filter changed in line manufacturer guidelines and keeping their car in a garage if they can. Even then, this may not stop a problem happening out on the road.”

As a member of the working group set up across the industry to get to the bottom of this issue, the RAC says it is working hard to amass and analyse its breakdown data to help find a solution.

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  • Nigel - 05/03/2018 11:33

    I also wonder how many EV drivers were caught out in the bad weather also -News not being reported on as it wouldn't be productive news currently?

  • Cross Climate - 05/03/2018 11:52

    I have just driven back from a ski trip to the Alps, where the much hyped in the UK "beast from the east" was just seen as a "colder than usual for February" with minus 18-20 during the day and minus 27 overnight. Needless to say everything worked absolutely normally, trains, busses, and shops even had bread!. Despite metres of snow in recent weeks, roads and even footpaths and laybys were clear of snow, ironic given that winter tyres are a legal requirement from Nov-April in most countries. As we are so bad at keeping our roads open, even with just a few cm of snow, there's an argument that many UK drivers actually need winter tyres more than our continental counterparts.

  • Edward Handley - 05/03/2018 12:56

    There is a lot motorists can do to prevent fuel waxing: first and foremost, servicing! A dirty fuel filter is much more vulnerable to waxing than a clean one. Second, there are plenty of diesel additives on the market which will prevent waxing if added to the fuel BEFORE it waxes. The major problem with waxing diesel inthe 80’s was due to reduced refining standards which meant there was more water in the diesel. No excuse now apart from lack of preparation!

  • Cross Climate - 09/03/2018 15:53

    I was in Austria week ending March 2nd, minus 25 every night and minus 13-20 during the day. I don't recall any issues with diesel cars littering the place and even my own Kia Sportage, known to have suffered in previous winters in the UK, was absolutely fine. It's UK fuel, and it's about time the fuel companies acknowledged it and provided the same fuel as mainland Europe.

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