99 SLE V6 thermostat help.

[synenergy52]

I changed my thermostat today. Seems to be a successful install. But I have two questions:

1) I stripped the third (hardest to get to) stud of the thermostat housing so I only have two "nuts" holding that housing down. There's no leaking but is this OK??? I cross threaded the third stud on accident The nut does NOT want to screw on to the stud. It seems to be tight.

2) There's a empty socket on top of that housing which looks like a plug should plug into it. I bought my car used and it seems they worked on the car/replaced the engine before. Could they have forgot a plug? The empty socket dips into the coolant in that metal tube and appears to be some sort of tempurature sensor or something.

3) Sorry--one more question... whats the jiggle valve for on the thermostat?

Here's a pic of the housing w/ the empty socket mine has.. with no plug! I searched my engine bay and there's no plug lying around



Here's the jiggle valve.. and another view of the 3 bolts that secure that thermostat housing down... The ones I secured are the top and bottom ones.