Izzu taking any stuff out? Like top wicks or silicone seals?
The innards of the likes of any Kanger is a closed up system. The silicone seal on the vent tube seals the tank on that part, and the combination of the coil and wicks (sorta) seals the tank there. (If the coil & wick area were completely sealed you would have a total vacuum - and that wouldn't work.)
If you take the silicone cap off the vent tube (some people do) that allows liquid to enter the tube leading to the mouth piece. If you remove top wicks from the coil that can allow too much liquid to enter the coil area - and up the vent tube or out the bottom it goes.
Or if you're just flying around in air planes all day all hope is lost. Keep your bottom coil device turned upside down in order to prevent air pressure changes from squeezing liquid out the base.