Coolant leak at thermostat housing

[NEW2DMAX]

Help!! I just changed out the water pump all went well except I now notice a leak - looks like it is coming from the line on the bottom of the thermostat housing that goes to the water pump.
It looks to be leaking right at the bottom of the housing around that line. Anybody know a fix for this, is there a gasket or o-ring inside the thermostat housing? I notice that line was pretty movable while I was installing the pump what seals that line inside the thermostat housing?

[DmaxMaverick]

There's an O-ring in there. You may have dislodged/damaged it during the pump R/R. You can pull the stat housing from the top and reposition/replace the O-ring (not nearly as much of a job as the pump). I recently helped a friend replace the water pump on a 2004 LB7, and that was a concern as well, but it didn't (doesn't) leak. The pipe had to be "moved" considerably to align the new pump, and I can see how too much pushing/pulling on the pipe could damage the seal.

[NEW2DMAX]

Ok I pulled the tube back off cleaned up the tube replaced the o-ring, greased up with some water resistant grease and a week later still have a leak not as bad but still leaking. Is there something i have missed.