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Questions and answers – Diesel fuel filter blocking


Q. I understand there is a problem with diesel fuel filter blocking causing cars and vans to breakdown?

A.Diesel fuel filter blocking affects a very small proportion of diesel powered cars. Less than 0.1% of the 10.5m diesel cars and 3.3m diesel light vans (approximately) in the UK were affected last year.  However, we recognise that for those motorists affected it is a major inconvenience.


Q. What’s being done to address the problem?

A. This is a complex issue and it’s being taken very seriously. A cross-industry group including fuel suppliers, motor manufacturers, motoring organisations and government officials is investigating the cause of the problem. It has not yet been able to reach any definite conclusions but work continues to try and identify the causes and develop a suitable solution.


Q. How can I (a motorist) reduce the risk of being affected by this problem?

A. The problem has not been linked to any particular fuel retail sites or fuel brands, nor has it affected particular vehicle makes or models. The working group has not yet identified the cause(s) of the issue and as such cannot identify any guaranteed means to reduce the risk.  However our general advice is to ensure your car is correctly maintained and you purchase fuel that conforms to the British Standard BS EN 590.  Most fuel retailers selling to this standard will make reference to the British Standard on their fuel dispenser. If the fuel dispenser is not marked please check with the retailer that it conforms to BS EN590.


Q. Are certain types of fuel more problematic?

A. No. To ensure the quality of the diesel they use motorists should ensure the diesel they purchase conforms to the British Standard, BS EN590. Most fuel retailers selling to this standard will make reference to the British Standard on their fuel dispenser. If the fuel dispenser is not marked please check with the retailer that it conforms to BS EN590. 


Q. Is the problem more common with certain brands of diesel and certain car makes or models?

A. No. The problem can occur, albeit very rarely, with any brand of diesel and/or vehicle combination. There has been no link made to any individual fuel retail site or fuel supplier. Nor has it affected individual vehicle makes or models or ages of vehicle.


Q. I’ve heard that breakdowns due to clogged diesel fuel filters are more common in cold weather?

A. Blocked fuel filters can be experienced throughout the year though the incident rates appear to increase during the winter months.  This issue is not related to the traditional issue of waxing as it has been seen at temperatures above when waxing usually occurs.  This is one of the areas that the cross-industry group is looking at.


Q. Is a breakdown more likely in certain driving situations eg. when on a motorway?

A. No, it could happen in any driving situation to any vehicle. If you do experience problems you should follow the standard advice given for procedures to take in the event of a breakdown.


Q. I have heard that the problem is worse when there is biodiesel mixed with diesel?

A. Most diesel fuel sold in the UK includes a level of biodiesel as standard. The cross-industry group looking at the overall issue has not yet been able to reach any conclusions as to the cause(s) of the problem.

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