****. I'm driving my early 2020 Octavia (mkIII) Scout (2.0L diesel DSG-7) through France, and only after I filled up (31L of the 55L tank) from the "diesel" pump I noticed the marking "B10" which apparently really exists about only in France, I'd never heard of nor seen before, and is officially (per Skoda) not compatible with this engine.

I don't find "B10" mentioned at all in the forums, and I find only few, vague mentions online in general about how B10 diesel (90% mineral diesel +10% bio diesel) can gum up diesel filters, degrade some engine parts, etc.

Anyone have experience with whether just (slightly less than) one single tank of B10 would be so noxious that I Shouldn't Drive It At All until I can get service to pump out the bad tank of fuel, or whether it'll be okay?

thank you,

Jay

If you haven't seen loads of diesels 'broken down' by the roadside so far in your journey through France then I would not worry about it.

Interesting perspective 😅.

(Apologies for my delay in replying. After resolving the B10 problem, I finished my drive to a horse farm in the French Ariège Pyrenees where I volunteered for a week, and did a 2-day excursion in the mountains on the inestimable Mérens horses (which, like Ford's Model T, come in any color you want, as long as it's black!).

I called roadside service, which came within an hour. (Spanish plate, Spanish auto club membership; while they were efficient at getting a French service truck to me, they didn't seem to bother using good translation to properly express the concern, and the very nice French guy who showed up thought that I'd put petrol into my diesel car, until I showed him the more nuanced concern).

He said that, despite Skoda's officially not having put their B7 diesel cars on the "certified okay with B10 diesel" list, that the one-time 2/3 of a tank fill-up with B10 wouldn't hurt my car - just to maybe run a tank of "premium" diesel, or add a container of diesel fuel injection/ system cleaner the next time I fill up.

Putting my "engineer" (I'm obviously not an automotive engineer, but I'm an engineer by training) hat on, from what little I could find about why B10 might not be good for some B7 diesel cars, I'm guessing too that during these 30°C+ days and with most of my driving being NOT local tooling around, there's also less chance of the B10 fouling anything at the moment, whereas during cold weather with short drives I guess it might be more of an issue. (What I read suggested that B10 diesel, if the fuel system isn't specifically designed to expect it, could build up waxy deposits that a B7-only system wouldn't handle by default).

Anyway, in the 350km I've driven since then, no obvious problems. I'll top up with a premium diesel this afternoon after another 120km on my way BACK to France where I WON'T touch anything labeled "B10" again.....

On 22/06/2026 at 14:54, Gerrycan said:

If you haven't seen loads of diesels 'broken down' by the roadside so far in your journey through France then I would not worry about it.

From memory the bio fuel can degrade certain seals etc. pus tends to clean sludge from tank and clog filters. Same as running on veg oil. I doubt one tank would cause any harm. Have had a few cars with no bio-fuel on fuel cap which I think means bio-diesel stronger than B7 but one tank of B10 shouldnt cause any lasting harm.

Alasdair

.Odd this says, E10, not B10. But other bumff says B10 not compatible.

ACEA_B10_compatibility_2022.pdf

Edited 3 July3 Jul by Evolution13

AI is getting better, but as far as trusting it???

Thanks @Evolution13 , indeed, I had found that exact document. (And I agree, I don't "trust" AI; but I do somewhat more often these days use it to find sources, then I go read the sources to see if what the AI thought it understood from the sources was accurate. Sometimes yes, sometimes not so much ...)