Mine whistles. It's the Boge clone from SureVapes (the cheapest one I could find). It's an incredible flavor machine otherwise, and very well built. I've found that if I adjust the afc screw a bit I can find a spot where the whistling stops and I can still vape. This KFL has the airflow and the control screw on the side, unlike others with the screw on the bottom. Apparently the airflow vent (not the one with the screw) can be bevelled slightly with a dremel or drill, which will stop the whistling. I'll give it a try at some point, but it's not a huge deal. I've also read that if you put a tiny piece of folded metal or a little bit of bent Kanthal in the air hole it will also stop the whistling. The air can still get through but the whistling is defeated because it changes the shape of the hole, which changes the path of the air just enough to discourage the whistle.