As I recall mine started with a pinhole at the rear of the engine at the clamp... where they almost always seem to begin their leaking. 2000 540i 150K on it.
Since the clamp area seems to be the weak point, I put a wrap of thick rescue tape under the clamp at both ends of the hoses. Not sure if I did anything good, but it certainly wasn't anything bad.
Missing my 2000 e39 540i 6 Speed Sport
"BMW's are well engineered, so they are fun to work on. You may want to put a TV in your garage" - TX530i