Mazda automotive coolants are green but they have almost NOTHING in common with conventional North American green coolant. Prior to the 2005 model year, Mazdas were equipped with a first generation P-OAT (phosphated organic acid technology) coolant developed and manufactured by CCI, the leading Japanese coolant company. P-OAT coolants rely on a combination of phosphates and organic acids to prevent corrosion; they contain no silicates or borates. In the 2005 model year, Mazda started using a second generation P-OAT coolant which has a lower concentration of phosphates and an improved organic acid additive package. The other major Japanese auto manufacturers, namely Toyota, Honda, and Nissan all use essentially the same coolant technology.
The only aftermarket P-OAT coolants are Japanese OEM coolants from Mazda, Toyota, Honda, and Nissan, Zerex Asian Vehicle coolant, and Motorcraft Specialty Green Engine Coolant (which reportedly is identical to the second generation Mazda FL22 OEM P-OAT coolant). For the record, Ford started using Japanese P-OAT coolant technology in many of its 2009 models (those sharing engine technology with Mazda) instead of G-05. Ford evidently found the performance of Japanese P-OAT coolants was superior to G-05 in Mazda engineered engines.
Using conventional North American green coolant in a Mazda is a bad idea. Even German (BASF) coolant technology as embodied in G-05, which contains silicates and no phosphates, is a much better choice than conventional North American green for vehicles with aluminum blocks and aluminum radiators. But a genuine P-OAT coolant, particularly a second generation P-OAT coolant like Mazda FL22 or Motorcraft Specialty Green, is the best choice.
The only aftermarket P-OAT coolants are Japanese OEM coolants from Mazda, Toyota, Honda, and Nissan, Zerex Asian Vehicle coolant, and Motorcraft Specialty Green Engine Coolant (which reportedly is identical to the second generation Mazda FL22 OEM P-OAT coolant). For the record, Ford started using Japanese P-OAT coolant technology in many of its 2009 models (those sharing engine technology with Mazda) instead of G-05. Ford evidently found the performance of Japanese P-OAT coolants was superior to G-05 in Mazda engineered engines.
Using conventional North American green coolant in a Mazda is a bad idea. Even German (BASF) coolant technology as embodied in G-05, which contains silicates and no phosphates, is a much better choice than conventional North American green for vehicles with aluminum blocks and aluminum radiators. But a genuine P-OAT coolant, particularly a second generation P-OAT coolant like Mazda FL22 or Motorcraft Specialty Green, is the best choice.