Answer 1 Until an expert improves this answer with the actual Chemistry reasons, I submit the following opinion. The colors which are added to anti-freezes, and oils and gasolines, are put there to indicate differences. The intermixing of different colored anti-freezes IS NOT RECOMMENDED because they have different characteristics, and are NOT COMPATIBLE. The practice will not, probably, cause immediate engine problems, BUT OVER TIME, will definitely result in degradation of the internal surfaces of the engine, and the entire cooling system. Therefore, don't intermix different colors of anti-freeze. Mixing colors of coolant in auto radiator
2015 10/22
Answer 1 Until an expert improves this answer with the actual Chemistry reasons, I submit the following opinion. The colors which are added to anti-freezes, and oils and gasolines, are put there to indicate differences. The intermixing of different colored anti-freezes IS NOT RECOMMENDED because they have different characteristics, and are NOT COMPATIBLE. The practice will not, probably, cause immediate engine problems, BUT OVER TIME, will definitely result in degradation of the internal surfaces of the engine, and the entire cooling system. Therefore, don't intermix different colors of anti-freeze.