Hi all,

It would seem there is a lot of (mis)information around about DPFs and reasons for failure. Apparently in one of the Nissan handbooks on one of their vehicles with a DPF it clearly states "this engine is not suitable for urban use"!

For info: Car / Van DPFs are commonly made of Silicon Carbide and are designed to hold the soot particulates (which we will all have seen coming out of some old vans / trucks). The DPF will block up if the exhaust temperature doesn't reach the level to force regeneration, typically between 500 - 600 degrees C. During regeneration the soot is burnt and reduced to ash (which stays in the filter, but will allow the exhaust gasses through).

Normal urban running, where the vehicle doesn't go over 30 mph will cause the DPF to clog with soot, and the exhaust temperature will not be high enough to reach the controlled burn condition - hence the need to run the car / van engine at a higher speed for a period. If you haven't got a dual carriageway or motorway nearby, keep it in a lower gear than you would normally use for 15-20 mins -it should do the trick.

Paul