Filling up your tank when it is half full (or half empty).  The more petrol you have in your tank means that less oxygen is taking up the empty space.

The best time to fill up your tow vehicle or motorhome petrol tank is when the ground temperature is still cold.  Usually early in the morning.  Which as rollers / campers is when you are usually up early anyway!

As petrol stations tanks are located well below ground, filling up at times when the ground is the coolest means that the petrol is the densest.  The cooler the ground the denser the petrol.

So what does that mean to us?   Buying petrol later in the day when the ground & tanks have warmed up and expanded means that one litre isn’t actually one litre.  As we are being charged for one litre of measurement not how dense the petrol is within that measurement. You get me 😉

Petrol bowser nozzle have 3 stages to control the flow.  Slow, Medium & Fast.  Pumping in slow speed will minimise vapours created by the tank while you are filling.  All bowser hoses have a vapour return.  What does that mean to us?

The heavier your hand is on the trigger the faster the flow, some of this petrol goes back to your tank as vapour which is being sucked back down into the underground tanks.  Basically you’re getting less bang for your buck.

Never fill up when you see a refuelling truck in the service station.

Its a sign that the underground tanks are empty and that the petrol you are putting into your tanks could stirred up and contain dirt and dregs. A fuel filter + labour + time off the road at the mechanic is not worth the hassle.