I drive a 2004 Dodge Ram 4x4 with the 4.7L. Recently I was driving it in Texas (where it was consistently over 100 degrees), and I noticed that the truck was running anywhere between 3/4 hot on the gauge to just below the H. The cooler it was outside however, the cooler it ran. I changed the thermostat, had the radiator flushed, changed the temp transmittor, had the fan clutch replaced, and changed out the serpentine belt (the water pump isn't leaking/making noise/showing any signs of issues). I took it on a 1300 mile road trip where the outside temp never got higher that 70, and it ran great. Yesterday, however, I was driving it on the interstate with the outside temp around 85, and it the gauge started creeping towards 3/4 hot again...ideas?

 

First thing to check is the 'stat. If the new one is sticking closed or is slow to open, that would make it run too warm. Any oil in the water or water in the oil?

 

yeah I checked for the head gasket, the oil isn't milky and there isn't any condensation in there...it runs strong, I ran it at 75mph for my whole 1300 mile trip with no issues, it isnt until the outside temp starts climbing that the engine gauge shows a corresponding climb in temp...

 

Kick the heater on full blast and see if the temp gauge goes down or up.

 

Your radiator is partially clogged and needs replaced. I would look into doing so as the 4.7L does not like to get hot and will pop a head gasket or crack a head if it does.

 

first off welcome to the exciting world of driving in the roasting texas weather.second it's a 4.7 thing if you find out what it is please let us know.I've changed everything includuing the rad.the only thing that i found that helped was an additive that goes in the rad. andhelps drop the fluid temp.I forgot whats it's called though

 

Just had to deal with overheating myself... Tried the t-stat first and it turned out the radiator was clogged.. If the radiator is clogged, be on the lookout for a bulging upper radiator hose..

Brian