New water pump and pissing coolant everywhere!

[350dieselsmk]

Alright so last weekend i was putting a new water pump in the super duty. got everything done and it is now pouring coolant out of the top of the thermostat. i just got the new housing and havnt installed it yet hopfully that will fix the issue but heres my main question. does the rubbed oring go in under or ontop of the thermostat?
Thanks
Will

[350dieselsmk]

alright so now i have a new O ring gasket new water neck and new water pump and its still weeping when i start the truck up. this is getting really old. any tricks? it says not to use silicon but im about to throw a little in there. any advice would be awesome
Will