This weekend me and my dad are changing out the thermostat on his truck and will need coolant to do this job. I have noticed on rock auto, the OEM ford coolant is yellow in color.

If I recall correctly, the coolant in his block is orange, which I believe is pretty much dex cool which to my understanding is a crap coolant.

My question is this: Should I drain the whole system and get yellow, or would mixing yellow and orange be ok, or should I just get orange to be safe?

Thanks.