I've been chasing this one coolant leak for some time now and I just can't figure out what it is. The coolant leak is relatively bad with having me fill the expansion tank once every morning or even more often. I first replaced the coolant tank and still the issue. Then about a week ago I did the coolant gallery including all the pipes in the back of the engine. And after all that it is still leaking. I took a camera and checked around the engine and everything by the gallery looks dry. I have read about that on the m62 the alternator is water cooled, and that the gasket on those sometimes seems to fail, and am wondering if anyone else had this issue, before I should tackle this.