Ask Honest John

Most recently answered dpf questions
I am soon to order a new car and am debating whether to have diesel or petrol. My driving pattern is changing as I am spending time between Italy and the UK. The problem is that when in Italy, I will...
With the fitting of particulate filters to petrol cars are we likely to see the same issues with regard to short journeys and stopping the engine during regeneration?
I currently drive a diesel car fitted with a DPF which has not been a totally satisfactory experience. I am considering buying a petrol vehicle which I understand is fitted with a Particulate Filter. Am...
How do I know if my car is in a DPF regeneration cycle? It would appear that the engine should not be switched of while this process is taking place but I have never seen any warnings on the dash board...
I would be interested in your opinion about DPF problems and whether some mechanics and main dealers make a big deal out of problems that are otherwise easily and cheaply resolvable? A couple of Polish...
I have a 2012 Mondeo 1.6 TDCi. I was in a traffic jam and the stop start was not working - the disable light was on and it would not turn off. I assumed it might be regenerating. Is it a mileage or when...
What sort of speed and for how long do I need to be driving for the DPF on my diesel to be working?
I read a lot about diesel DPFs but how do I know when the fuel system is regenerating? I drive a Toyota RAV4 2.2-litre diesel. Nothing comes alight on the dash board and only once did I smell hot oil?
One of the problems with diesel engines for low mileage users is the clogging of DPFs. Petrol particulate filters now seem to be appearing, so are they likely to have similar problems?
I have the opportunity to purchase a well looked-after Nissan Navara 2.3-litre diesel auto. It has 9000 miles and was first registered in May 2016. The owner is fastidious about the care of every car...
 

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