That's odd. I've got 3 iClear30 and never had any problem with them. Generally little to no vapor and gurgling are signs of the clearo being flooded. Have you removed the clearo and made sure there's no juice or condensation accumulation on the connector of the battery? Then, try blowing through the drip tip to insure it is clearo's airway is open & clear of juice.
If that doesn't help. Do a couple of short (3 - 4 sec) dry burns (fire button on without vaping) and see if that helps. Sometimes juice residue accumulates on the wire coils and needs to be burned off.
You didn't say how long the heads have been in use; it may be time for them to be replaced.
iClear 30 - Replacement Atomizer Head - AltSmoke
Aside from that, I'm stumped of what your problem could be.