What mileage to prevent DPF issues?

I have heard that low mileage on a diesel car can be bad for it. I have heard this can damage the DPF and other things. Many people think about the maximum mileage they consider to be ok when they purchase a used car. My question is this:  take the popular BMW 520d for example. What is the minimum mileage I can consider as being ok on a 2010/2011 car?

Bill Hughes (Dublin)

Jan 2014 Filed under: DPF issues

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Expert answer

Hi Bill,

There’s no one blanket answer to this, as much depends on where you do your mileage and how you drive. Basically the issue is one of heat. The DPF needs the exhaust system of the car to reach full operating temperature in order for it to burn off the excess carbonised soot that it filters from the exhaust. If you don’t generate that heat then the DPF gets full and clogs up and causes problems. So, you can do relatively low mileage, but if it’s mostly on the motorway and you’re running at a constant 120km/h for, say, 30 minutes or so each day, then you probably wouldn’t have any problems. If you do lots of miles but they’re all in town, stuck in traffic, creeping along, then it doesn’t matter how much mileage you do, you’ll have problems. As a rule of thumb, we usually say that circa 20,000km a year is the changeover point, but as I say, driving style and where you do your driving enter into it too.

Neil Briscoe - Complete Car Advisor
@neilmbriscoe