Left handed threads.
Hi, nope, the threads are right handed on both ports. This way you could tighten up the valve a tad. Yes it will loosen the outlet port some. Maybe it wont leak though. If one was reversed it would pull or push the pipes. If there isn't any give in the pipes you could crack the manifold. Actually with PVC pipe I doubt you could even unscrew it all the way.
You hit the head on the nail with how you suggested to fix it. Glue and teflon tape. I do have one thing for you to check first. Make sure the leak is coming from the fitting and not from the diaphragm near the screws under the solenoid. Those valves will leak right there after a while. Try tightening the screws a tad. Maybe even a new diaphram. I'd hate to see you cut the valve out of there and re-install it then find out there's still a leak.
Good luck!
If I can't fix it, it's broken!
This post has been edited 3 times, last edit by "mrfixit" (May 24th 2008, 8:41pm)