That may be true of the TDi and the XEDi but the newer common rail diesels such as the TD5 in the Disco and the TD4 BMW engine in the Freebie are more refined modern units that - If I remember correctly - are not suited to ECO fuels such as recovered cooking oil.
Modern fuel refineries supply to a variety of customers who may have their own specific requirements, but I have never noticed any specific difference.
However, I did notice a difference when Low Sulphur Diesel was introduced.......
I had an old Transit LWB 2.5ltr naturally aspirated diesel - good old workhorse for lugging large items about.
When I moved house I noticed after a while that I had lost about 50 miles off the tank range - from approx 450 down to 400 a tank full.
.. it wasn't until I read an article about Low Sulphur diesel reducing your MPG by about 10% that I realised that I had been filling up at a Shell garage near my original house - and, when we moved, filling up at a supemarket near my new house that sold only Low Sulphur.
I then did a specific test over several tankfuls and found that 10% loss to be true. At that time the lower price didn't stack up against the lost mileage.
Should also be noted that the Refineries change the Diesel mix to a "Winter" fuel around October to prevent the old waxing up problem in cold weather. This is changed back to a "Summer" mix in the Spring.
Those of us who have been long term Diesel users will remember when Diesel not only gave a better MPG, but also was quite a bit cheaper than Petrol. This changed when the Gulf war started and the Military needed a helluva a lot more Diesel - it became scarcer and the price shot past that of petrol.
For some reason
this has never been reversed with the reduction in hostilities.The latest Petrol engines are so efficient that, if you buy new, then you won't recover the differential in overall costs in a 3 year period runng a Diesel.
