Overheating more slowly after thermostat, radiator hose change, and radiator flush...Whats the deal?

Alright, 1997 Chrysler Concorde. Took off the radiator and flushed it, changed both upper and lower radiator hoses. At the time, I figured I would see if I could also flush the flow of water through the engine. I stuck a hose in the thermostat housing and it flowed through...So I took it off to change the thermostat, and someone had removed it totally. So I put a new thermostat, new thermostat housing, both radiator hoses, and flushed the radiator. The coolant reservoir isn%26#039;t leaking, but the cap is. However, it is still overheating, just not as quickly. The water pump is working, the top hose gets hot. I am thinking there is a possible clog in the return line from the reservoir to the engine/radiator, but does anyone else have any ideas? After changing everything (also new coolant, 1gal concentrated, rest water) it idled for a while, but the coolant bottle never dropped the level. It stayed full completely. Any ideas?|||You could have air in your cooling system and make sure that the thermostat you change has the right temperature. Also make sure that your fan works.|||Hopefully you don%26#039;t have a warped or cracked head, Be sure the cooling fan is working , It bothers me that the thermostat was gone when you checked it ! Hopefully you did not just buy it ? That is an old used car salesman trick to unload a junker !!!!!!|||Sounds like the thermostat isn%26#039;t opening up. Once I changed my coolant fluid and put in 100 %. My car would heat up slowly but eventually overheat. I then learned that coolant doesn%26#039;t dissipate heat and it needs 50% water to get rid of the heat build up.|||You stated that the reservoir isn%26#039;t leaking but the cap is. If the cap is leaking then change it. If the coolant system doesn%26#039;t reach the right pressure then it will not cool properly. Also try checking to see if the fan is coming on when it is supposed to. I hope this helps. Good luck.|||try running a total cooling system cleaner through radiator and the engine block. see how much gunk comes out.