Leaks in DE filter

The pool is finally rebuilt, the water clear and ready to go (but that's another story).

What I'm concerned about is a leak coming from the air bleed valve on my DE filter. It's not like I'm losing significant amounts of water from the pool, but when I twist it shut, the water just pours out the air bleed hole and even out the top a little.

Any tricks of the trade I need to know? Would teflon tape help? This is only the second season I've used it, but could it just be that I need to replace that part? It's a little yellow thingy ;)