G48 is the BMW stuff. Provided that you flush your coolant often, the green stuff is just fine. It's the requirement for longer service intervals that bought about the need for long life coolant formulas such as G05.

Even the green stuff that's available today has different chemistry to the stuff that was available in the 70's when these cars were new and is unlikely to cause the damage that the old stuff did if left for too long.

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With best regards

Al