I`ve heard rumours, that it is best to purchase your diesel for your car, early in the mornings.
As it is thicker then, and you get more for your money.  Is that right, or is it myth?


 

Yes, I think I got that,  ( you know your stuff!)     so not worth me going to fill car up, at the crack of dawn.

Sorry just my daft mind

Petrol / gas expands more than diesel and is affected by external temps to a greater degree so you are possibly right Gerry but there is very little fuel in a petrol pump and the rest is stored under ground where the temperature is virtually stable so no effect there then and as you pump the fuel through the petrol pump the area affected by the ambient temperature is cooled by the fuel passing through.

Long story short and the same for any fuel IF it is stored in mass above ground then the ambient temperature can have some effect on its volume, now I don't know any public garage where volatile fuel is stored above ground.
Where it is stored it is normally kept in twin skin vessels (tanks) this reduces external effects.

If you filled your fuel tank completely to the top in the early morning and then parked your vehicle all day in the sun then the expansion would cause your tank overflow to let the expanded fuel out which you have paid for so you loose. though the construction of fuel tanks is such that there is 99% of the time an air gap trapped in the tank, even when the fuel is at the top of the filler neck.

I would say you were lucky in that the can did not rupture.
I try not to have fuel in cans and when I do I only have half filled then give the can a little squeeze to push out some of the air that gives room for some expansion through vaporization if it happens.

Mmm  Tech head on again (could I charge for this?) well err TGID has a valid point, while petrol does not suffer so much with condensation as opposed to diesel both fuels do float on top of water!
which is where the "rusting out" comes from Oh before I forget modern fuel is cleaner than of old so therefor there is less harmfull oxides within it.
Back to the real thing, and just to please you TM.  Diesel is an oil and contains lots of stuff to make it burn cleaner Oh and remove the "knock" from the engine. (that horrible clanking sound that diesel engines make) Diesel oil has a detergent additive in it to help stop particle sludging then it has other much for other things all of which when allowed to warm then cool then warm etc create moisture ie water. this lays in the bottom of the fuel tank and if the inner coating of the fuel tank becomes damaged then = drip drip drip
This is similar for petrol being that there is a lot less in it but it is highly flamable (its refined to a greater degree) as above and the moisture and the tank coating.
Did I not mention the tank coatings?    Old cars / trucks etc had steel tanks much the same as today, only now the insides are coated with a special paint to combat the effects from the fuels and moisture's. (I m enjoying this)

So NOW FOR THE GOOD BIT.......
There are products on the market that you can add to your fuel tank to dispurse ALL the water / moisture accumulated within not only your tank but ALL your fuel system  £ 3:00 ish depending on where you get it.
To name a few companies STP, Castrol, Whinns Slick50.

In a nut shell stick a bottle of stuff in each tank and forget the rest! 

PLONKA!!

Yes you were very lucky to get away with that and you are right diesel in petrol cars is worse because petrol and diesel are ignited in different ways petrol is ignited via a spark but diesel is done with compression and is injected at a high mist pattern