did you make sure that you got the 510 threading?
I would remove the tank from the base of the iclear 16 d. then remove the cap that goes over the coils and wicks. there should be a small piece of wick sitting on top of the coils, remove that and then put everything back together. this should help open up the draw of the tank.
EDIT: this will open up the draw, I did not see your last post