Dangers of exhaust particulate filters clogging up

Lex is warning fleets who buy new generation diesel engines with Exhaust Particulate Filters (EPFs) that they risk reliability problems if they don’t heed manufacturer operating recommendations.

Drivers who drive mainly in urban areas are most at risk of their EPF clogging up and their car having to make regular trips to their local dealer.

In the case of some Lex drivers this has meant visiting their dealer once every six weeks or so to have the filter unblocked as their driving occurs predominantly in traffic at low speed.

According to manufacturer guidelines, unless an EPF equipped diesel engine is operated at 50mph for at least 20 minutes, or covers 50 miles at motorway speeds at least once every couple of weeks, there is an extreme risk of the EPF clogging up.

These driving conditions effectively burn off the soot particulates which the EPF has been equipped to prevent from escaping into the atmosphere.

Most cars have a warning light which notifies the driver that their EPF is blocked and that the car needs a run out at 50mph for a prolonged period. Other warning lights encourage the driver to take the car into their local dealer.

“If a driver knows their car is going to spend most of its time in urban areas at low speed, then it’s worth avoiding a car with an EPF,” explained Jamie Wiseman, Maintenance Manager of Lex, which spends over £80m on maintaining its fleet each year.

“We would probably recommend a driver opts for a petrol engine in this type of scenario or a diesel without an EPF,” he added.