Hi everyone I stumbled on this page and I though of setting you yanks straight because your clueless.
Diesel is a different fuel to unleaded petrol, subsequently when you fill a diesel tank the diesel foams like waves in the ocean. If it hits a still surface it foams more than if it hits a moving surface. You belly flop into a still pool in you back yard. It hurts more than a straight dive into moving water ( like if your mates are splashing in the water)
What keeping the motor running does is it keeps vibrating/ shaking the truck, bus what ever, and with it the fuel tank so it minimises the amount of foaming by decreasing the tension on the flat layer of diesel in the tank.
If you didn't keep you motor running it would take 3 times longer to fill up and half your diesel would end up on the floor.
Also you almost light a bonfire next to your truck while filling diesel
DO NOT TRY IT. I would make that clear because you yanks need to be told everything. In Australia we have this thing called common sense, which even here in Australia doesn't exist anymore, lets call it uncommon sense.
The static electricity build up can create a spark between your car and the fuel nozzle that's why petrol cars have to turn off before refuelling. When I refuel my petrol cars I always turn off the motor
When you fill your petrol cars you see the evaporation?
That vapour is what will catch fire if you smoke next to your petrol car.
Diesel on The other hand Is like motor oil, it comes out so low in the refinery that it doesn't evaporate
I have set you yanks straight and done my public service for today I'm going to bed because its 3.40 in the blessed A.M. Here in Brisbane
I wish you health and happiness