Leaking coolant bleed screw

Is there a knack to shutting off the coolant system bleed screw (the one thats mounted on top of a hose near the battery on a 20vt). I used it to bleed the system a while back and noticed yesterday that its leaking .. no amount of turning it seems to fully shut it off.. do they have a tendency to break ?

Is that the one in the hose that goes to or comes from the interior heater? I have never needed to touch mine, just been patient in bleeding by leaving the coolant reservoir tank cap off and running the engine up to temperature...

Maybe they do go "off" with age? If the screw comes right out maybe you can try to put some PTFE tape on the threads? But you'll need to partially drain the coolant again to avoid making too much of a mess.

yes its on top of the hose coming out of the bulkhead presumably the return from the heater matrix... ill see if i can get it out and try some ptfe then ... maybe get the whole hose changed at some point