on the freeway truck is getting hot, iturn on the heater it helps but is still hot,can drive all day in the city traf.an it will not get hot? It's a 4x4 2004 ram 4.7? Tks

This link should:

https://www.askmehelpdesk.com/cars-t...tml#post235973

Be sure to purge any air from the system. Check for combustion leaks.