Lower radiator hose cold

Just replaced 4.2 engine in my 2007 Trailblazer.
It runs great! Noticed when engine is hot the upper radiator hose is hot. Meaning thermostat is opening. But my lower radiator hose is cold.
Is that normal? Temp gauge reads about 210.
Do you have to burp theses systems like the older Chevys?

Yes it could be air bound, look for any bleeders around the t'stat housing, or just leave the cap off overnite. front of car jacked up some if possible.

Maxwedge,
Thank you for your reply. Don't see any bleeders, but will try leaving the radiator cap off overnight and lift the front end.