Ask Honest John

Most recently answered dpf cleaning questions
I’ve recently bought a used car on finance with a deposit of £1000. On day three of having the car (less than 50 miles later), the engine management light came on. I rang the dealership and took it in....
I have a 2008 BMW 3 Series Touring 3.0d. I do 20,000 miles per year on A roads, at high speeds, and change the oil and filter very regularly. A diesel particle filter warning light has now come on. Why...
My Mazda 6 has a particulate filter warning light flashing, despite two hours on the motorway. The car has never done this in four years of ownership. It's done 99,000 miles. Does the DPF need cleaned...
Is it okay to clean the DPF filter with Mr Muscle oven cleaner and then put it back? It’s a lot cheaper than replacing it but does it do the job? I have a Vauxhall Vectra 1.9 DTi that’s done 120,000 miles...
The DPF on my BMW 5 Series is blocked. Can I add something to clean it as I only do short journeys, or should I give the car a good run on the motorway?
I have a 2011 Peugeot Partner which has just started displaying a 'risk of filter clogging' warning. I took it for a run on the dual carriageway, but it hasn't made any difference.
You say the underlying maintenance cost is the reason for the collapsing of diesel car prices. I'm concerned because I own a 63 reg Ford Mondeo Estate 2.0d, with 40,000 miles that I plan to keep for another...
The DPF on my 2009 Jaguar XF was professionally cleaned after going from amber to red. The car had done high mileage (104,000), so I was kind of expecting it. 13,000 miles after the clean, it went straight...
I own a 2011 Audi A6 Allroad 3.0 TDI 240PS 6 speed auto with paddle shifts (98,000 miles). Other than 10,000 mile oil changes, what would you recommend doing to keep this on the road for a few years? It...
I'm a Motability hirer. For three years, I have driven a diesel Nissan Qashqai 1.5 and had no DPF problems whilst doing mainly short runs and covering 20,000 miles. My real mpg is approximately 45 - 60...