Ask Honest John

Most recently answered diesel engines questions
You frequently advocate the use of Shell V-Power Nitro Diesel which I have used in my Citroen C5 from new. You also state that diesel engines are prone to suffering from clogged up DPFs at 80,000 miles,...
I am thinking of buying a Toyota Land Cruiser. I do approx 11,000 miles per year, mostly short journeys but with a couple of 100+ mile round trips a month and a 500-1000 mile round trip every three months...
My 2013 Ford Focus diesel has developed a knocking sound on the gear change between 1st-2nd-3rd. The car has also started making vibrations through the whole car when at idle speed too, it gets to the...
Do you reckon the Jaguar XE diesel is a good option to replace my 2011 Mercedes-Benz C250 CDI?
We are looking for a used car to tow a horse box long distances. The vehicle must be capable of pulling 2000kg plus. We have a budget of around £5000 and have been looking at the Kia Sorento 2.5 diesel...
I have read in a number of places that is a bad idea to run a diesel car on low fuel. Apparently you should never let it go below 1/4 of a tank. Is this correct? And if so, why?
I accidentally put 6.3 litres of petrol into my diesel Ford S-MAX. The car has since been towed home. Should I fill it up with diesel to dilute the petrol, or simply pay a firm to drain it?
I have a 2014 BMW 530d, and it is EURO6 compliant but does NOT have the Ad blue tank. Yet my previous Audi A7 V6 diesel and other Audi 3.0 litre diesels had this technology. How is it that BMW achieve...
We own a Ford 2010 Ford Mondeo 1.8 TDCI. Yesterday, the car started but then stopped almost immediately. It then refused to start. We have tried again today, but it refuses to run for more than a few seconds....
I own a Vauxhall Vivaro van with a 2.0-litre diesel engine. The vehicle is displaying a DF059 fault code, which states the particle filter is absent. What does this mean?