Definetly on wrong then yes haha.
Just use RTV for a gasket. If you can run a nice 1/8" bead of RTV around thermostat housing and then go full circle around the thru holes. or do like me and smudge it on all sloppy then smooth it out
.
Also make sure the thermostat doesnt slip out of its little groove when installing the housing, it should be easy to tell if it does. But that will forsure cause it to leak as well.