dude, be careful what coolant you put in. mixing the wrong coolants is B-A-D. definitely do a flush and fill, but i'd try to stick with the same "type" if possible. my research suggests there will always be remnants left over even after a flush and fill. and when you flush, be sure to use distilled water. do some homework. color was originally used to help distinguish different types but apparently even that doesn't even hold true. read about the fluid contents.
the following link is just "one" of many articles i read before flushing and filling mine last year. i don't even recall if this one had all the details, just one i happened to save.
Coolant Info
good luck.