I have a 1997 1500 5.2 it's been parked for a while and I replaced Plenum gasket last summer and entire dash so this week was first drive in a year or so, problem is it will not run at normal water temp, the water pump is barely 2 years old, I replaced thermostat last summer and once again this week along with the temp sensor. When I start it up it takes about 5 minutes and the temp hits exactly halfway between 200 and 260 and STAYS there doesn't move at all. I've tried burping the system, I know for a fact thermostat is good, sensor is brand new as of today. I do run heater on high when I burped it, it didn't blow hot air hot until I revved it a little, also I watched for when the thermostat opened, it did it when it was already reading about 240 then after it opened it went to 225-230 right at halfway. Definitely doesn't feel like it's overheating nothing is crazy hot. Just find it strange that it stays at that temperature, doesn't rise or fall.