Wish it was a TII

I popped the hood today on my 88 GXL after driving around for about 20 minutes or so, and I noticed several (about 10) small droplets of some green fluid (antifreeze) on the black plastic covering of the intake. It looks like it splashed there somehow. The location is immediately behind the chrome radiator cap. Also, just to the left of the radiator cap, there is a small black "bolt" with a wire coming out of it, on top of the radiator tank. It looks like there is a very small amount of ?antifreeze? leaking around this "bolt".
Anyone know what this "bolt" with the wire coming out of it is for? It looks like a sensor of some sort. Also, any ideas about how to fix this leak, or what could be causing it? It doesn't seem to be leaking very much, but I'm still concerned.
Thanks!

dr0x

Just pull it out and put some thread sealant of some sort around it, then put the sensor back in.

Amur_

The mystery bolt is your coolant level sensor. Be gentle with it - the wire likes to break off and they're goddamn expensive to replace.