Need some HVAC help

[04Ram08-2500]

Got an 04 ram 2500 that I just replaced the heater box in. New heater core, evap coil and heater treater blend doors. We pulled system down properly and charged to spec with evac/charge station. My question is I am getting heat but it doesn't stay hot long. Will jump up to about 98 and then starts to fall. I checked all my actuators before reinstalling and all were good. The ac control system has been replaced also. Anyone got an idea? Thanks!

 

[kevkev]

Sounds like air needs to work out of your coolant system. I did the same as you and mine roast me out.Did you flush your system?

 

[cheffrank_357]

I heard somewhere you have to " burp" your system
I am not sure how but mine came out ok after replacing the radiator

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