I suppose you could have some kind of blockage which is stopping the flow of coolant through the radiator and possibly popping the hose off the radiator.
how old is the radiator?? These radiators don't last much beyond say 8-9 years, so it might be time for a radiator change (really pretty simple to do).
Maybe the water pump is janked... I suppose one of those being out could pretty well stop the flow of coolant.
I'm sure you'll get a few more responses by others who are more familiar with your engine setup.
you can always check out www.bmwe34.net till you hear something, and don't forget to search the forums, lots of good answers already posted in previous posts.
Originally Posted by SkyWalker