Ask Honest John

Most recently answered dpf questions
Is it true that new cars such as the Land Rover Discovery Sport use automatic engine management adjustments to keep the particulate filter clear even if no long journeys are done?
I have a 63 plate BMW 520D (F10)  Auto Efficient Dynamic version (Euro 6) As I drive a lot on motorway, the car has a high mileage, close to 180,000 miles. I had a "driven chain, check soon" message pop...
Is it possible to purchase anything that lets you know when your diesel particulate filter (DPF) is regenerating e.g. something simple like a bulb lighting up?
I currently have a 2014 Mercedes-Benz C-Class diesel and I am waiting delivery of a new B-Class 180d. I prefer Mercedes diesels to Renault petrol engines. Because I only do around 8,000 miles per year...
I want to buy a small van for our dog walking business. The Peugeot Partner/Berlingo/Cargo Life are absolutely ideal for our needs. It is lots of stop-start short journeys so we looked at the 1.2-litre...
Four months since buying a 2014 Mazda 3 2.2-litre diesel and on the day of collection the DPF warning light came on. The garage has attempted to repair this but after several attempts the issue remains....
Is the MG seven year warranty any good? The catalytic converter has failed (or the particulate filter) after only three years. Is that acceptable to be excluded from cover?
If the DPF is blocked in my Ford Kuga, how will I know? What is the cheapest way to deal with the situation?
Can the Toyota Proace diesel van be used for short journeys? I believe it has a DPF.
I have a 2012 V70 2.0-litre diesel with just over 70,000 miles. It's extremely quiet and comfortable with no rattles, knocks or squeaks and I fill up 2 out of 3 times with super diesel. Living in rural...