Ask Honest John

Most recently answered diesel particulate filter questions
I bought my 57 plate Passat 11 months old from main dealer, a Volkswagen demonstrator, serviced by them since. I have had major problems since day 1: Almost all major components have been replaced, ie...
I have just watched your excellent video on the new Ford Ranger. You make the point that, when cruising on the motorway, the engine will be revving at 2000rpm. Will this be enough to activate the DPF?...
I'd apprecate advice, please. Have had a 2005 Mondeo TDCI LX from one year old; now done 60K gentle miles, 1500 of them towing lightweight caravan (950kg). Main concern is cheapness to run, mainly avoiding...
I seem to remember you saying that if there is a period of low speed, short journeys the engine should be run at 2000revs+ for a period of 15 minutes each week in order to regenerate the Particulate Filter. My...
I have Focus Estate 1.6tdi(110) which is due for its 6-year service and my local Ford dealer tells me the DPF is due for replacement at a cost of several hundred pounds. The car has only done 55k and...
I take delivery of a Hyundai i40 diesel in March and have read your posts about Particulate Filters with interest. 4 My mileage has fallen dramatically since retirement and I now complete small journeys...
Just had 23H9 VW Passat injector recall done at Local VW dealer, after a couple of weeks and long distance runs DPF and engine management lights lit up. Is there any possible link between the newly replaced...
I have a 1.6TDCI C-MAX on 2011 plate. The mention of DPF keeps rearing its ugly head. Diesels use less fuel so pollute the planet less (in theory), but as they are now they are fitted with DPFs. My...
After each of two years my BMW 520d has shown excess oil in the sump. Is this because attempts to clear the particulate filter have dumped fuel into the sump? I now recognise that this is probably the...
I have ordered a Vauxhall Meriva 1.3 diesel from Motability. Do these cars have any dpf problems? I do aproximately 15 miles each way on the motorway a couple of times a month, will I have a problem with...