Ask Honest John

Most recently answered diesel cars questions
The oil appears to be reading high in my diesel E90 BMW 3 Series, both via the dashboard indicator and also by manually checking (after driving approximately seven miles and leaving five minutes to cool)....
The DPF warning light has come on in my Audi Q3. It had the emissions update in March 2017. Audi have said that they will charge me £60 for diagnostics. If the problem is caused by the update then they...
Can you please advise how to regenerate the DPF on a Mercedes-Benz E-Class?
I have a 2008 Renault Koleos 2.0d. In the past two weeks I've done four journeys in excess of 50 miles at high speed (dual carriageway). A couple of days ago, a warning appeared saying "check exhaust emission"...
Although I really like my diesel Mazda 6, I had no knowledge regarding the DPF i.e. short runs not doing it any good. Are there any other cars with as good a spec as the Mazda 6, which are less complicated?...
Our 2012 Volkswagen Passat 1.6d appears to over-rev when changing gear, but at the same time as the rev counter rises, the engine loses power. It has been recalled and had the emissions fix done. Do you...
I had the emissions fix done on my 2012 Skoda Octavia 1.6 TDI on 10 October. My car went into limp mode and showed two warning lights yesterday. I drove to my local garage, where they told me injector...
What are the drawbacks with particulate filters?
I have a 2007 Peugeot 207 1.6 HDI, with 83,000 clocked miles. Basically, the longer the car sits unused, the more blue smoke it puts out when it starts and also the harder it is to start (cranks slower...
I was sold a brand new Nissan X-Trail diesel almost two years ago. I told the dealer that we only travel around 8000 miles a year and now I'm being told the car needs £300 of work due to not being driven...