If you dump gasoline on a fire, it will go ‘fwoomp’ and try to climb back into whatever container you poured it out of. If it succeeds, that container may even explode. Which is bad, and why people die or get terrible burns from pouring gasoline on fires.

If you pour diesel on a fire, the fire will get bigger and none of those things will happen. Unless, apparently, like the poster above, you pour so much on it so fast it drowns it before the diesel can get up to temp. Apparently. I’ve personally never tried that.

Diesel is basically cooking oil in many ways, and you can do the same thing with cooking oil too if you want.

This is well known by every redneck I’ve ever met, and I’ve personally done it numerous times.

P.S. also, putting gasoline on cold fuel in warm climates makes a pretty cool fireball due to said flashpoint. Just, you know, don’t light it from close up. Cold climates? No problem.