The Kanger T3's are some moody little clearomizers, I'll tell ya that...
I got 4 of them, all the MT3, with the solid color tank with a clear window. Bottom "head" assemblies are identical. All of them have 3 air holes, and are a bit loose on the draw, so I plug a hole with a toothpick and that problem gets sorted easily.
The leaking comes from two areas...
The first area is the seal where the metal tube in the tank assembly mates to the mouthpiece... If this isn't sealed properly, it will allow
juice to enter the mouthpiece if the T3 is placed on it's side, as well as create a gurgling effect, because you're sucking air from the tank side AND the air tube... This can be corrected by using a sharp tool to flare out the small metal tube just at the base of the inside of the mouth piece. I use an ice pick... The user who suggested this as a leak point initially used a pair of scissors. What you use is up to you of course!
The next area is a poor seal at the wicks. This one is a bit more tricky. If the wick is too small, it will flood the coil, and due to the nature of the design, is going to allow
juice to leak from the air passage in the center pole all over the positive connection of your battery. When this happens, you get all kinds of issues, like your device having wishy washy resistance readings. This really screws with VW mods bad, cause they attempt to compensate by adjusting the voltage to match the new resistance value. This ends up supplying nowhere near the amount of voltage you need to truly fire the coils, and just messes everything up! LoL The other end of the spectrum is the wick being too big... That will result in not enough
juice making it to the coil, and you can burn your wick, getting a burnt or muted flavor.
The wick issue is a weird one... Lots of folks try lots of remedies... What works for me is changing out the wicks in favor of 4 1mm silica wicks in the coil, and no flavor wicks... This gives me a good flavor, good vapor, and no leaks... That is, no leaks until the juice level gets to be around the junction point where the air tube meets the head assembly... Then it leaks just a tiny bit... Not sure why this is...
I think the T3's are great when they are working, and a real PITA when they aren't... They are easily serviced to make them perform better, but it takes time, and that's a load of garbage when you buy a brand new product. It should just work... I like that they don't require any crazy angles or twisting or anything to get the wicks to suck up fluid like a top coil clearomizer does (Vivi Nova / Stardust / T2). But the leaking issues are pretty unforgivable.
It's a flaw in design, IMO... Rather than traditional wicks they could have used a filler material (even if that were just coiled wick) with small holes (think a pre-punched carto) that feed juice to the wicking material. Basically, make it work like a cartomizer.
Better yet, just throw out the whole design and use a cartomizer and tank instead... LoL
Bottom coil clearos are a good idea, and I applaud Kanger for the effort with the T3, but it needs some work...