I had my radiator hose bust, naturally my temp went up pretty high but I changed the hose and it was fine. I was trying to figure out if when the temp goes up like that if its possible that the thermostat got so hot it was damaged. I also only have pretty much all water in the radiator, which I'm changing back to antifreeze today. The temp has been fine, but when I got it on the highway after about 70mph the temp started to jump. Anyone have answers for me I'd really appreciate it

 

change your thermostat.
and add antifreeze. 50/50

 

The temperature shouldn't rise in the cooling system at speed unless there is an issue with the coolant, the circulation at the Water Temperature Sensor, or the radiator is not receiving air flow. When my fan relay went out, the only time I felt confident my car wasn't going to overheat was when I was on the highway.