[Brian in Oregon]

If the tank on my FJ40 is topped off, the gas will expand and dribble all over the side and onto the ground. Quite a bit too, enough to leave a trail down the driveway. This happens particularly in warm or hot weather, but it will also happen in winter if the temp during the day rises by 15 degrees or so. So, I never top off my tank.

Interestingly, the oil companies are fighting having to put on fuel temperature compensating metering devices in the USA, because the average expansion of fuel works in their favor. In Canada, the oil companies want such equipment, because the average contraction of fuel there costs them money.