Ask Honest John

Most recently answered additives questions
Am I wasting money by occasionally purchasing Esso Supreme? I do this with the idea of it perhaps cleaning the engine and parts of my Mazda 5 Sport. I do only 2000 miles a year.
I drive a 2007 Volkswagen Passat 2.0TDi 140 SE saloon. Could you please advise me if using Millers Diesel Power ECO MAX fuel additive is worth the expense? I normally fill up with Shell diesel but I do...
I run my 1960 Standard Vanguard using Miller’s VSP Power Plus as a lead replacement additive. I have now acquired a 1967 Triumph 2000 which has been run using Castrol Valvemaster Plus. Can I safely replace...
I have an old-school 2.0DTI in a Vauxhall Zafira. I have had issues with the EGR valve for about three years. Instead of having it replaced my local friendly garage "cleans" it and all is well, or was...
The DPF light suprisingly came on after a motorway run between Liverpool and Northumberland. I tried the usual of driving as the manual stated, but an extra light came on saying take to garage! I couldn't...
There is no Shell filling station locally so I use BP 'Ultimate' - but here it is 10p/litre dearer than'Regular' unleaded. Is there an additive that I can buy to use with 'Regular' and get similar benefits...
I have just spent nearly £7000 having a 1968 Volkswagen Beetle 1200 restored, in addition to paying nearly £2000 four years ago for a new Vega engine. I have been alarmed to hear of the increasing quantity...
I currently run a 2006 Honda Accord 2.2 i-CTDi and have been using Shell V-Power diesel fuel exclusively. I was just wondering what your thoughts are and why you singled out BP Ultimate diesel as your...
Some 2-3 weeks ago you ran a letter about problems with diesel fuel blockage caused by the addition of biodiesel to standard diesel and lack of use of the vehicle. I have a smallholding and two tractors...
I normally add some lead substitute to the tank of our 1980's Series III Land Rover. The other day I didn't (because the garage didn't have any on its shelves and I then forgot about it). So with a full...