Got this inline port for a water temp sensor and it has a screw in it. I thought it must be for air bleed, but the hole does not go all the way through. I got two of these, and they are the same. All the other ones online (for other size hoses) also have the screw.

WHAT IS THE SCREW FOR? I'm thinking about drilling it through and using it as an air bleed. That would be highly convenient, and I can put this in the place of the black plastic air bleed adapter that is there now.

Also, BTW, all the videos and threads I have seen say there is a second air-bleed for the cooling system. I swear there is not one on my 2006 JCW, unless it is directly under those couple of electrical connectors on the right side of the valve cover (as you look at the motor from the front, driver's side). I have looked and looked. Can anyone confirm the '06 JCW does or does not have 2 air bleeds?

 

That screw is to hook up a ground wire for a sensor that needs a ground (most electrical ones do).

You can always use the sensor as a bleed by removing it until all the air is gone, then reinstalling it.

 

Thanks! My sensors do not have a ground. Bleeding through the sensor is a good idea too - I've done that, but I'd rather not un-do and re-do that seal so often. It seems like moving the radiator out of the way is a common thing to need to do, at least while I am in the upgrade and fix mode.
I am going to drill it through and see if it will easily seal. I have two of them, so can sacrifice one if needed. Actually, I bought two with the other one intended to be a drain. I bought a 1/8 NPT petcock fitting (is that the right word?) so all I have to do is turn/open it to drain the radiator instead of moving the radiator out and disconnecting the hose. I'll post a photo of that when I do it...