If you think it may be the spacing between the coil and the airtube leaking, take a gasket from another coil and add it on top and see if that solves the problem.I should have given more info -- that's what I've been doing and it keeps returning. I am wondering if I am screwing the coil down too tight, or maybe leaving it too loose. It's a 50/50 juice that has worked well in the Mtanks all along. Hate to pitch a new coil, but I just might. I have gotten spoiled to the perfection of the M - gurgling used to be so commonplace!