This may be a really dumb question but I have a very rudimentary engine knowledge base. I am having some cooling issues with my 2020 Beck Speedster with subaru engine. Granted, I live in Texas and it is already in the mid 90's, but the car has been running a little hot when I am out driving. Carey and the guys have been great with helping me figure out what the problem is, but I had some free time to look into things and did not want to bother him on his weekend. Today, I noticed that the radiator fluid seemed a little low. My question is this. What coolant should I be using to top off the radiator as well as to add some to the overflow?