Van heats up to about half way up the gauge, then hit the highway and it overheats, pull over it cools down, replaced thermostat, flushed and burped the system, new coolant, there is circulation, no slime on oil cap or sign of water in oil, does this with the heater on and off, up until a week ago the gauge never went up a 1/4 of the way, and the van runs great

 

Welcome to DF
Does your van still overheat when driving on the freeway? And do you know if the radiator fan is coming on?

 

Yes it over heats on the freeway, and yes the fans are coming on

 

The fan on at highway speeds is ineffective. I read that at any speed over 30mph has sufficient airflow to for cooling and the fan shouldn't be running. Are you only using the dash gage to determine if it's overheating or are you using other diagnostic methods? Have you tested your thermostat? Take it out and put in a cup of boiling water. Have you checked or replaced the water pump?

 

Check the radiator for blockage, something that may stop air flow. I agree with 22dodge22, remove the t-stat and drive without one and what the temp does.

 

Take a garden hose and clean the radiator and condensor. It might be as simple as alot of dirt/bugs clogging up the fins in the radiator. I had an intrepid that developed an overheating problem and after spending the money to replace the radiator with no improvement, it turned out the black paint on the aftermarket a/c condensor I had installed was flaking off and causing airflo blockage.