I hadn't realized how fortunate I've been with Kanger heads until just recently, hearing of so many issues that people have with them. Out of some 30 Kanger coil assemblies I've used, I had one that was DOA. It was a T2 top-mounted coil, the one with the long wick. I think the coil wire was either broken or disconnected on one side. When I installed it, I let it sit for 30min to allow the wick to soak up juice. When I tried to fire it, I got nothing at all. I thoroughly cleaned the threads and connections on the tank and on my eGo, but no change.
All the other "29 or so" of my Kanger coils have always performed just fine for me. No leaks/flooding, no dry hits and all of them lasted anywhere from one to two weeks (going through about 3-4mL of juice per day).
When I started using Kanger coils, I noticed that my G50 - a Hypertank clone which uses the same single-coil units as the Protank II - was fussy with the way its coil was installed. I quickly discovered that the force with which the silicone gasket on the coil body pressed on the bottom of the air tube inside the tank affected whether the tank would perform well or have problems.
Pressing together too tightly would cause the gasket to warp, resulting in leakage. Pressing together too lightly would cause juice to seep between the weak connection between the gasket and the bottom edge of the air tube, resulting in leakage. I finally found that tightening the coil unit into the G50's connector/base snugly, then unscrewing it about a quarter-turn would prevent leaks every time.
On the other hand, my Protanks like their coils to be firmly screwed into the base cap without backing them off at all.
(I haven't yet encountered any significant dry hitting in any of my tanks, so I don't have experience with that as a "tank issue".)
Since I started vaping, I've heard numerous users of Kanger tanks report an early failure rate in coil units of somewhere between 20% and 40%. The failure rate I've personally encountered with Kanger coils is 3-4%.
Thirty coils, even though they were purchased from a variety of vendors all over the U.S., isn't quite a large enough sample pool to allow me to speak definitively about the reliability of Kanger coils. But I do think I've been very fortunate to date. I hope it holds on, because so far, my favorite tank of all I've tried is the Protank 3.
Regarding removal of flavor wicks in PT coils... I only tried it once, myself. Actually, I didn't do it on purpose. I was washing a tank and its current coil when I decided to open up the top (chimney) of a Protank II coil and get more flowing water onto the wick material. You know, keeping the coil assembly clean and all in hopes of extending its life. Well, as soon as the chimney came loose, two short, previously captive pieces of silica immediately jumped for their lives out of the coil body and down the sink drain. I didn't have any more loose silica bits lying around at the time, so I figured I'd test the "new configuration" to see if it could continue to function without its two little friends.
You know how they always say, "Don't drink the e-juice?" Well, now I know why.