bigdog said:
Garvin said:
Fuel going off, evaporation, condensation! Where do you get all this 'information' from?
Easy. In a life a long time ago in a galaxy far far away called South Dakota. We would have wild swings in temperature. 108F summer down to -33F winter. This could play havoc if one didn't keep the tank full during winter. I even mounted a 35,000BTU aux kerosene heater to preheat the fuel and coolant in my FedEx lorry. At -20F #2 diesel turns nearly solid. Any condensation in a petrol or diesel system will freeze in short order. So, 1.3 million miles later over the course of ten yrs. I've seen & learned a lot of trivial BS stuff.

lay:
Err ...... umm, I'm not sure most here will be too worried about 108F summers or, for that matter, -33F winters. Indeed, I believe that most on this forum will have petrol engines, unless they've modded their Z4 somewhat, so waxing of the fuel shouldn't be a major concern nor freezing of the negligible condensation that may form in the fuel tank from the ingested air.
Regarding the other comments on evaporation, well most systems are pretty much closed so any signifcant evaporation will take years and I'm not sure modern fuels will crystallise out solids (deposits) even if significant evaporation did occur.
I think most can sleep easy about any problems with their fuel, whether the tank is full or not.