I’m at a lost right now and don’t want to just start throwing money and parts at it so here I am. My 2014 ram 1500 5.7 started out with a failed t stat because it would not open until about 213 and then after initial opening it would continue to work as normal but the night driving home it stayed shut and would not open and temp slowly rose until I had to stop. So when I finally made it home I opened her up and noticed fluid was leaking from where the water pump mates up to the block and ordered a new seal instead of just replacing the pump. So with new t stat and seal and all new coolant I thought I’d be good to go but no. After replacing the new t stat it will initally open at 215 and then after initial opening it works as normal, but once oil is up to full temp the coolant will start to slowly continue heating up but only at highway speeds. It has normal temps driving around town. So I’m looking at a new radiator and t stat but don’t know if I’m poking in the right direction.

 

Any oil in the coolant or coolant in the oil. I'd pressure test the coolant system and if coolant comes out the water pump weep hole, it's bad. What kind or T-stat did you put in?

 

No oil in coolant and no coolant in oil. T stat was a Murray 203 degree from oreilys. I’m thinking the leak was from a bad seal or improperly cleaned mating surface. Since new seal it has not shown signs on leaking

 

Radiator cap???

 

Is there a way I can test it to see if it’s faulty?

 

With a pressure tester from auto parts stores loan a tool.

 

Alright thank you

 

Was not the radiator cap

 

Okay. If you access to an infrared temp gun. You can measure the temp on your radiator in different areas and if there are noticeable cold spots. Tell you if circulation through your radiator is good/bad. If you do replace the T stat don't buy the "fail safe" kind. Lots of problems with those. Stant makes quality ones.