Ask Honest John

Most recently answered premium fuels questions
Is it a good idea to use premium fuel in my 2018 Ford Fiesta 1.0-litre?
My daughter is waiting to collect a used 2017 Kia Sportage from a Kia dealership. Your articles have often recommend drivers using Shell V power fuel. Will my daughter gain the same benefits from super...
Could you please advise which is the better petrol: Tesco 99RON or Shell’s 98RON?
I have read that buying premium diesel will help prevent the DPF from blocking up as it has additives in it. Is this true or am I wasting my money?
My Avensis has done 82,000 trouble-free miles on supermarket petrol. If I now start using Shell high octane fuel, will I get a sudden release of carbon deposits and would this damage the engine? I have...
I know you are an advocate of premium petrol so I have been using Shell V-power. Are there any others which are just as good?
In a national newspaper recently they made a statement saying that branded petrol is no better than fuel bought at supermarkets. I know that you are an advocate of good grade fuel and as such, I have been...
I see there are various types of additives that claim to keep turbos clean. I would like to know if they work? What can an owner do to keep the turbo oil feed and return pipes clean?
I have just bought a 1990 Mini Moke, but the dealer is not sure if the cylinder head has the hardened valve seats to use unleaded petrol. Do you think it would be okay to use unleaded? Also, should I use...
Is the diesel fuel that I can buy in a supermarket filling station really any different that the diesel that I can buy from a Shell or BP garage?
 

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