the .9 petrol and diesel rip off

vansboy

AdrianHi wrote: »

Just what I was thinking.
Is it true or a myth....
Get your fuel early in the morning when it's cold and the fuel is more dense and you'll get more fuel than if you do it when it's warmer / later in the day?

No, it's not a myth.

Don't try it, but if you tanked the vehicle on a really hot day, left it parked in the sun, then you'd find the fuel would expand to such an extent, it'd build enough pressuer to escape through the vehicles venting & when you remove the filler cap, it'd spurt out.

It's only a small amount of potential savings, in reality, though.

VB

Pew_Pew_Pew_Lasers!

It is a myth, because the tank is contained in the ground, which remains at roughly the same temperature no matter what the sun is doing.

david39

The problem of temperature shrinkage is a valid (but miniscule) one for the motorist but is on a much larger scale for the petrol station. Some stations will receive fuel from a storage depot that is a separate location than the refinery that produced it originally. This petrol will be at normal air temperature, so the volume they get is the volume they sell.

Fuel coming out of the refinery plant comes out very hot and is pumped into vast storage tanks before loading onto tankers for delivery to garages in the local vicinity. The average temperature in these tanks is way above the ambient air temperature. When it reaches the petrol station it is still at a higher temperature than the surrounding air. Underground, over time, it cools down and, of course, shrinks. The garage then sells a lesser volume of petrol than it receives. The difference can be several percent. On a tanker carrying really hot product on a cold day, you can stand alongside it and feel it radiating heat.

For many years, petrol companies ignored this shrinkage despite complaints from forecourt operators, but it does amount to a significant loss, especially when so much of the value of the loss goes to the Exchequer.

Now petrol companies have to measure the temperature of the product before it is delivered and make a correction to the volume invoiced to the retailer depending on the difference between it and the local air temperature.

If you want to be penny-pinching, don't buy your petrol from a station receiving a delivery - it might mean you buy hot product that will shrink in your tank.

tomstickland

As long as they round up or down to the nearest integer then there's nothing wrong at all. If they always round up then your total fill up costs, at most, 1p more than it would have done. In which case the price per litre was approximately 1/6000th more than shown.

tomstickland

AdrianHi wrote: »

Just what I was thinking.
Is it true or a myth....
Get your fuel early in the morning when it's cold and the fuel is more dense and you'll get more fuel than if you do it when it's warmer / later in the day?

That depends on the thermal expansion rates for the pump versus the fuel.

forgotmyname

Add another bit here..

How many times have you put exactly £20 in and then go to put the pump back & it adds a penny? Ive seen it several times now to think i am not making it up.

spaceboy

I expect the round up if it comes to .5 or more and round down if it's below .5 - if you ever did maths at school you'd understand...