Another common problem, particularly with GT clones, is that you can easily push the chamber and cap down with the top cap tube upon screwing together. I check every time now, but without a proper seal at the top of the chamber cap, you'll have leaking, gurgling, and a generally impossible time making the GT work properly. I used to notice when I was driving and had prepared a new tank, only to discover that this cannot be easily remedied while driving, lol. The O-ring at the chamber cap can also become loose, or may be of poor quality to start with, causing leaking, as well. I generally have replaced all of my O-rings on the GT's to eliminate this problem. Another problem with O-rings is that they can be too loose at the bottom of the chamber and then turn as you screw the top cap and tube in place. This results in pulling on the coil and wick, generally unsettling the careful wick placement at the slots, again causing leaking. Again, replacement of the O-rings can fix this. They don't all do this, but I have two originals, two different clones (total of 5 GT's), and some are tight, others, not so tight. Anyway, I have had problems with all of these areas.
For me, the importance of a micro coil (an ID of 0.045 - 0.055 inches) is so important that I wouldn't change the ID to try to fix the wicks at the slots. I changed from cotton balls/rolls to KGD, which has a vastly superior compression, allowing me to put more wick through a smaller ID coil, providing greater "girth" at the slots. Since changing to KGD, I have not had any slot leaking problems, once I zeroed in the right wick width and size.
One last point, if the wicks are too long, the tubes can grab the sides, or the base tube threading, and pull the coil and wick out of place, again causing severe leaking. So, while it sounds like a lot can go wrong, and it can, a quick check of the mentioned four areas of potential leaking will allow a leak free vaping experience, in my experience. Prior to learning each of these points of "vulnerability," I had leaking through the air hole about 20% of the time. Also, as the juice in the tube decreases, once you lose the pressure seal, all bets are off. The negative pressure seal is what allows the juice, which sits above the open air chamber, to NOT leak out the hole. So, keep your tubes full of e-liquid to avoid this fifth possible problem. Two cents...
