Hmm strange. Wont close but everythings screwed in tight...
Dimensions dimensions....
Coil too high...
You sure you got the right coil in it? :s
Have an inkling might be the wrong coil, slightly too big, wedged itself into the base, possibly will have fucked the threading on the base up which might explain why your struggling to unscrew it, and if coil is too tall, the top cap although will screw onto the coil, the topcap will be sitting too high and thus wont seal to the base...hence the leak..