Hi,
BMW says to use coolant free of nitrites (NOT nitrAtes). I have had K-bikes since 1997 and have used Prestone, Wal-Mart's brand and Texaco anti-freeze, mixing them, as per BMW, to a ratio of 40% coolant and 60% distilled water. I haven't had any problems. The silicates problem came about in HONDA motorcycle engines, NOT BMW motorcycle engines. The silicates caused leaks with the Honda seals. They do not cause the same problem in BMW engines because the seals are of different types.
BMW says to use coolant free of nitrites (NOT nitrAtes). I have had K-bikes since 1997 and have used Prestone, Wal-Mart's brand and Texaco anti-freeze, mixing them, as per BMW, to a ratio of 40% coolant and 60% distilled water. I haven't had any problems. The silicates problem came about in HONDA motorcycle engines, NOT BMW motorcycle engines. The silicates caused leaks with the Honda seals. They do not cause the same problem in BMW engines because the seals are of different types.