Hi Rammstein:

___It (regular gasoline/petrol) doesn’t expand immediately and it doesn’t expand a whole lot. I always fill my tanks right to the fill neck to maximize range as well as minimize tank calculation errors but most don’t and it is not a recommended practice given the vapors are not exactly earth friendly. In any case, what goes in is what goes in. There is no expansion to worry about given the 55 – 60 degree F gasoline (it is in an underground tank after all) has cooled or warmed up your fuel tank to the same by the time it is filled. Any evap afterwards heads up the vapor recovery HW unless you fill that like I do every once in a while

___Good Luck

___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___Waynegerdes@earthlink.net