If your tank is leaving puddles on the desk, the liquid is getting past a seal it should not. Where the drip appears tells you exactly which seal, so you can stop guessing and stop wiping.
The short version
- Liquid at the airflow ring nearly always means a flooded or loose coil.
- Liquid at the 510 base or between glass and metal points to an O-ring.
- Thin, high-PG liquid in a sub-ohm coil leaks through the wick holes.
- Fill to just below the top of the glass, never right to the brim.
The drip tells you where the fault is
A sub-ohm or MTL tank only has a handful of places liquid can escape: the airflow ring, the 510 connection at the base, the joins either side of the glass, and the top cap. Each one has its own cause.
Before you change anything, dry the whole tank with kitchen roll, stand it upright on a clean tissue for ten minutes and see where the liquid appears. That one test saves you swapping parts that were never the problem.
Liquid on the outside of the drip tip is a different issue: that is usually condensation or spitting, not a leak, and it has its own fix in our gurgling and spitting guide.
- 1Drip tip
- 2Top cap and fill port
- 3Glass and chimney
- 4Coil head
- 5Airflow ring
- 6510 connection
- 7Mod: screen and buttons
- 8Battery bay
Leak finder: start here
Pick the spot where you found liquid after the tissue test. Each answer is the most common cause for that location, so try it first before anything else.
If the tank leaks from two places at once, fix the airflow cause first. A flooded coil pushes liquid everywhere, and once it is sorted the second leak often disappears on its own.
Bear in mind a tank that leaked once after a flight or a hot car is not faulty. Air pressure and heat push liquid out through the wick, and it settles once the tank is back at room conditions.
Where is the liquid coming out?
The coil is flooded or not screwed in firmly. Empty the tank, unscrew the coil, check it is seated straight, refill and blow gently through the drip tip with the device off to clear excess liquid.
Check the coil's bottom O-ring and the base O-ring are present and not split. Re-seat them and hand-tighten the base, no tools.
An O-ring has shifted or the glass is chipped. Take the tank apart, seat the O-rings flat and check the glass edge for nicks.
You overfilled or the cap is cross-threaded. Fill to just under the top of the glass and close the cap slowly.
The liquid has to match the coil
Coil wick holes are sized for a certain thickness of liquid. A big sub-ohm coil around 0.15 to 0.4 ohm has large holes made for thick, high-VG liquid. Fill it with a thin 50/50 or nic salt and the liquid floods straight through the cotton and out of the airflow.
An MTL coil of 0.8 ohm or more has small holes. It copes fine with 50/50, and very thick 80/20 liquid can be too slow for it, which causes dry hits rather than leaks.
If your tank started leaking the day you switched liquids, this is almost certainly why. Use 70/30 or higher VG shortfills in sub-ohm tanks and keep 50/50 and salts for MTL setups.
Sub-ohm coil (below 0.5 ohm)
Thicker liquid stops flooding through big wick holes.
MTL coil (0.8 ohm and up)
Thin enough to wick through small holes without leaking.
Very thin liquid in a sub-ohm coil
Classic recipe for an airflow leak.
Reseat the seals properly
O-rings are the little silicone rings that seal every join in your tank. They stretch, flatten and slip out of their grooves over a few months of coil changes, and one missing ring is all it takes.
Strip the tank down over a clean towel so nothing rolls away. Every tank comes with a bag of spare O-rings in the box, and if you have lost yours, check our spare parts. A smear of e-liquid on each ring helps it seat without twisting.
Hand-tight is tight enough. Cranking the base down with force squashes the rings out of shape and can crack the glass.
- Empty and strip itPour the liquid back into the bottle, then unscrew the top cap, glass section and base.
- Inspect every O-ringLook for splits, flat spots and any ring sitting half out of its groove.
- Swap tired ringsUse the spares from the box. Wet each new ring with a drop of e-liquid.
- Seat the coil straightScrew the coil in until it stops, without forcing it past that point.
- Reassemble and fillHand-tighten everything, fill to just below the top, and stand it upright for five minutes.
Habits that make tanks leak
A lot of leaks are not faults at all. They come from how the tank is filled, stored and vaped, and they stop the day you change the habit.
The big one is filling down the centre. On top-fill tanks the chimney in the middle goes straight to your mouth and the coil; liquid poured down it ends up in the airflow. Aim the nozzle at the side of the glass instead.
Lying the kit on its side in a bag, leaving it in a hot car, and flying with a full tank all push liquid out through the wick. Store it upright and carry it with the tank no more than two thirds full when you travel.
Leak myths, busted
Some fixes get repeated so often they sound true. Tap each card to check the reality before you waste a coil or crack a glass.
The common thread: tanks are designed to be sealed by soft silicone and a correctly seated coil, not by force. If you find yourself reaching for pliers, something else is wrong. Also worth knowing: a brand new coil can leak for the first few minutes while the cotton finishes soaking, so give it time before you blame the tank.
When a tank still leaks after new O-rings, the right liquid and a fresh coil, the threads or the glass are damaged. At that point a replacement tank is usually cheaper than chasing the fault.
Quick answers
Why does my vape tank leak from the bottom?
Usually a coil that is not screwed in fully, a missing O-ring at the base, or liquid that is too thin for the coil. Check those three in that order.
Why does my new coil make my tank leak?
New coils can flood if they were over-primed or if the tank was filled before the coil was seated properly. Empty, reseat and refill with the airflow closed.
Can I use my tank on a plane?
Yes, but cabin pressure changes can force liquid out. Carry it two thirds full or less, upright, and expect a little weeping you can wipe off on landing.
How often should I change tank O-rings?
Only when they look split, stretched or flat. Many vapers swap them every few months or whenever a leak appears.
