My 2009 1,3-litre Ford Bantam has a 54-litre fuel tank but I often find that I can get more fuel into it. Why is this?
JOHN BROWN – By e-mail
Most fuel tanks have an extra air space above the fuel to allow for expansion. This space is usually about eight per cent of the tank capacity and reduces the risk of the tank bursting in an accident. It also prevents fuel from being forced out on a hot day due to expansion and will restrict potentially harmful fuel vapour loss to the atmosphere. This explains why vehicle fuel tanks usually have a larger actual volume than the stated capacity.
This situation is made worse by the way forecourt attendants are trained to fill fuel tanks to the maximum extent possible. One should make sure that fuel filling is stopped at the first automatic pump shut-off.
