Nope. When your engine is hot it's fine (viscosity is a function of temperature) and a two tank system uses pure diesel to get up to temperature. Otherwise mix it in the tank with diesel and it's thin enough.

Of course I'd never do that in practice, as that would be tax evasion. Even if veg oil is half the price of diesel, I'd never consider it, Officer.

I have seen set-ups with a heater element in the cooking oil tank to warm it up before use

"seen"?

well, seen discussed online, but I think there were photos etc

(nod)

Your secret's safe.

Not from the feds.

<Feds> Don't bust his door down yet. We need better evidence. Follow him and check the exhaust for an odour of chips. </Feds>