My 2005 yukon runs hot. It has a new thermostat, h2o pump, head gasket?
on 2005 GMC Yukon

Replaced old cylinder head as well. The engine coolant hot message comes on after about 20-25 minutes.

Asked by for the 2005 GMC Yukon
Did you do both sides?
Just one, the other side was fine
Maybe not!...... Suggest a combustion leak test. How about the radiator and cooling fan(s)? Try a scanner to see what the computer says the temp is, guage may be wrong.
There are no leaks anywhere, but I do recall not hearing fans on when I had to pull over
The COMBUSTION LEAK TEST is for CO (carbon monoxide) content in the coolong system, if the liquid used in this test changes color, you still have an internal engine problem. No doubt about it if this test is done right! If it is overheating at road speed (55mph) for say 5 miles, then cooling fans really dont come into play, however if overheating sitting still or slower speeds, fans may be a problem. Was it doing the 'same' thing before the work you did??