Short term I dont think there would be a problem with mixing. But, you said you wanted to do the best thing and a flush was a possibility. Then, be sure to drain the engine block too, flush and drain completely with a water hose and refill with the BMW coolant. Improper mix of coolant (too much water) or use of non DI water can lead to electrolysis and the aluminum block will be eaten. Not to mention the radiator "chalking" up. Check all your hoses and have a nalgene clearly labeled with a 50/50 mix in your trunk. I have seen nice write ups in Pelican Parts web site. |