Your thermostat or water pump might be the problem...
Or you didn't get the air purged from the cooling system when you filled it back up.
When engine is cooled or carefully open radiator and run it, after engine reaches normal temperature see if water circulates inside radiator, if not, then you have a restriction, thermostat or pump issue. What did you fix?
Looking for a Used Ram 1500 in your area?
CarGurus has 12,990 nationwide Ram 1500 listings starting at $1,495.
Search Dodge Ram 1500 Questions
Are you a UK consumer? CarGurus now has a discussion forum in the UK.
Dodge Ram 1500 Experts