oemcoolant

So i have a 2015 mustang gt and i wanted to top off my orange coolant. I know ford changed to that “yellow” coolant and is backwards compatible with the current orange coolant. Does anyone know if I should just mix it with the yellow coolant or just do a complete flush and put the yellow...

What is the oem coolant? I just bought a mishimoto rad and I wanted to know what the oem coolant is so I can fill it up with the correct stuff. I have a 2019 GT.