Water pump OEM BMW or GMB

I've used GMB some 10+ years ago. They were made in Japan and came with a lifetime warranty.

Sounds like your water pump is shot. The impeller is spinning on the shaft and not pushing the water. I just had a customer who had this problem. The crazy thing is, I just replaced the pump about 2 years/30K ago with a GMB pump. He had the exact same symptoms as you: car gets hot, but does not overheat, no water through the return line, and fan takes a long time before it turns on.

Well made, but they ain't cheap. Here's the diagrams for the N54 setup: http://www.realoem.com/bmw/par...fg=35 The water pump itself is over $500.