Do you think your Toyota can sense what color dye is in your coolant? Huh? I personally don't mix the colors, but if you do it's OK as long as the ingredients are the same. As long as the ingredients are the same, that is what counts. There may be others, but as long as it's a phosphated OAT (HOAT) with no silicates, no borates and no amines, you are good to go. There are a couple of non-Toyota coolant brands that I know of that fit the bill: Beck/Arnley, Pentofrost A1 (Made by a German company named Pentosin), Zerex Asian Vehicle formula (but I can't find it in concentrated only pre-mix). BUT, it does not have to be the Toyota red or pink coolant, as long as the ingredients are the same. This means that most coolants on the shelf at your local auto parts store will NOT fit the bill. The coolant should be made out of ethylene glycols, phosphates (inorganic acid salts) with Organic Acid Technology (which makes it a Hybrid Organic Acid Technology or 'HOAT'), no silicates, and no borates or amines (2-EHA is an amine). I came to the conclusion that there is a specific type of coolant that the Asian engineers decided works best in our cars. I researched this almost an entire day a while back. Perhaps I can help with the coolant issue. Someone posted this on ToyotaNation and thought it gave some insight to the coolant madness in today's cars, especially Toyota:

Toyota super long life coolant pentosin