I just purchased this truck at auction, it's an '05 Ram 1500. The truck overheats and I do not know why; I have tried replacing the thermostat as well as flushing the cooling system. I would turn on the heat and that would bring the temp down if I was at a traffic light, but now with the new thermostat it seems to overheat even faster. Last night even at one point, there ws no hot air coming out of the vents when i tried that trick. The truck said it was overheating, but this time underhood temps didnt seem that much. (I can verify that the radiator was boiling at one point yesterday, so it's definitely getting hot).

Any help is greatly appreciated, i'm trying to try all my options before I go for the water pump.

Thanks.

 

Did you bleed your coolant after installing and flushing? Sound like air in the system to me.

If that is not the case I would guess a plugged up system @ the heater core.