[Closed] Tubeless valve leaks .......

yup
[url= http://www.chainreactioncycles.com/stans-no-tubes-presta-removable-valve-core-2014/rp-prod38822?utm_source=Google&utm_medium=Shopping&utm_name=UnitedKingdom&gs=1&gclid=CLbRmMiGocMCFaXLtAodhhQASQ&gclsrc=aw.ds ]Core[/url]

Best check the rubber hasn't split where the valve enters / exits the rim. Had a similar slow leak and realised there was a slight split that began to leak when tightening down the screw on nut.

Presta valves have a little leak I find when you unscrew them, but all sealed after screwed back up.

If it's a removable core valve, make sure the core is firmly screwed in place unless you want to remove the core. Has flat sides you can do it up with a mini spanner.

Then, use plenty of sealant generally and it will all seal up.