Do you want the Road Tax system to change? Do you have thoughts on the potential changes to the Road Tax system? | No thanks
Any - Bio-diesel - Kiwi Gary

I recently attended a technical paper on "diesel bugs" as they are commonly known, given by a gentleman from UK who researches such matters. He related an incident that he had recently with his new diesel vehicle when refuelling at quote a major supermarket netwrok that sells its own brand fuel unquote. They sell the new ultra-low-sulphur-diesel mandated by the EU for next year, including the bio-fuel proportion.

His problem appeared to be that his car fuelling pipe kept blowing back and triggering the handpiece shut-off, so he went back to the supplier and complained. Not so, says the supplier after trials, so back to the supermarket. Using his credentials, he got to be present when the supply lines were opened up. UGH !! The filters were blocked with gunge that resembled yellowish grease. In his laboratory, the stuff turned out to be yeast which had violently multiplied. Investigation showed that yeasts love bio-fuels and, in the presence of only a small amount of moisture [ far less than the usual diesel bugs,] the yeasts multiply.

The deposits had turned inside-out a witches-hat filter that normally sat apex towards the incoming flow, and blocked the final filter in the handpiece. It was that final blockage that was triggering the handpiece shut-off.

He expressed concern at the possible results of the gunge getting into the ever-increasing pressures in common-rail injection systems. At present, the only really safe escape after such contamination is a full strip-out , clean, and sterilise. Because different yeasts enjoy different bio-fuels [ cooking oil, corn oil, rape-seed oil, etc.], there is not yet a chemical bug-killer that covers all yeasts.

Why has it not come to notice earlier ? Although not proven, the research suggests that a proportion of sulphur acts at least as a restraining mechnism on the yeast multiplication rate. [ That is suggested as the reason why the big container ships with their cathedral diesels burning 5% sulphur fuel have almost no diesel bug problem ]

Diesel drivers may wish to keep this knowledge stored away in case you suddenly have trouble filling up.

Any - Bio-diesel - Brit_in_Germany

One of the selling points for Aral's Ultimate Diesel in Germany is that it is biodiesel (FAME) free. Since Aral is a subsidiary of BP, it could be that BP Ultimate Diesel is also bio free. Worth asking at the till.

Any - Bio-diesel - Med

Hi, I am not sure if this has anything to do with the above subject but i'll go ahead and ask anyway.

Bio-fuel is now at 7% at the pumps as confirmed by Shell and other leading stations & as an example my handbook for my Mazda 6 2008 2.0d (with DPF!!) says do not fill the tank up with NO more than 5% bio-fuel as it can cause sever engine damage. Now, one time the dealer told me to use the "more expensive" fuel such as BP Ultimate as its better for your engine.

That confused me because not everyone has the funds to fill up with the more expensive option whilst the pumps are too expensive at the moment, i looked into it and found out that the legislations had changed for labelling on the pumps. I have had a bad experience with my DPF system and also found out that putting more bio-diesel in the car (obviously without realising because its from the pumps) that because of some levels of sulpur and the amount of bio-fuel coming from the pump when the DPF needs to regenerate is uses a small amount of fuel to burn off the soot...but because the diesel has a highher content of bio-fuel the engine is not designed to burn it off because it needs to burn off at a higher temp.

Does this not mean that by using for example a shell petrol station we are all invalidating our warranties??


Ask Honest John Right column

Value my car