I would suggest 3 things, given the age of the tank the first is just a safety issue
1 ) Check the insulator on the negative block for any melting, this is done by completely removing the second bottom screw (negative block post and air tube), and while that post is out check the underside, you'll find another plastic insulator only it is round, use a small screw driver to force it out to inspect this insulator as well.
2 ) Check and clean the bottom deck (especially the juice channels), clean the threads of the coil chamber barrel, any gunk that could build up might be in these and could lead to liquid blocking
3 ) Russian wicking that has never failed me. Thread it through the coil, pull it up to install the barrel, trim the wick about 1mm to 1/8th inch over the barrel, wet wick, then tuck it down carefully along the build blocks onto the deck in an "L" shape back against the build block away from the juice channels, this "L" shape when liquid flows up, if the wick is tucked down right, the liquid will come up and rest on top of the lower arm of the "L" instead of just coming up to maybe barely touch the bottom of the wick as I seen in your posted picture.
hth, but I think #3 is your issue