Ask Honest John

Most recently answered dpf questions
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 have a 2014 Porsche Macan 3.0-litre diesel, bought new. It recorded 42mpg or better on a long run and 39mpg average on short urban runs. Porsche wrote asking for the car to have a software update for...
My Volkswagen dealer has advised against carrying out the emissions software update on my Golf Plus because they say there is a fault in the exhaust gas recirculation valve. The car drives fine and no...
My Audi Q5 has a smell like hot tarmac around the rear and exhaust area after a good run. It doesn't smell like oil and the oil level is steady after 500 miles. No smell under bonnet or car sides. What...
I want to trade in my 2011 diesel Nissan X-Trail 2.2 for a slightly smaller 4WD. I commute 50 miles a day, but need a 4WD for rough farm tracks. I have a budget of about £20,000 - £25,000 after trading...
My 2016 Toyota Yaris diesel fuel consumption meter indicates a large increase in consumption for about 25 minutes every 350-400 miles. Is this the DPF regenerating?
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 had the emissions update on my SEAT Ibiza 1.6 TDI Sportrider. Eight weeks later, the turbo blew. SEAT tried to blame me by saying there was too much engine oil. I got an oil sample done and the oil was...
I stumbled across a couple of issues which seem to do the rounds on various forums, so I thought I'd ask here for a definite answer. One is that the Start-Stop mechanism, as implemented in the Audi A6...
The emissions fix was done on my 2010 Volkswagen Golf 1.6 TDI in January 2017 and it now drives very differently. The DSG gearbox changes up into seventh gear much earlier than before (at around 40mph)...