Car overheats with no signs of flowing liquid in upper or lower hoses. No signs of any leaks, and I've removed the thermostatic. Still no flow.
Overheating on 1991 BMW 735iL
Not sure if these cars have a plastic impeller on the water pump like other BMW, some Ford engines, some Jaguar and Audi/VW engines, The impeller fails and slips on the water pump shaft, car overheats and runs hot due to poor circulation. Call a local BMW specialty shop and ask them have they seen the water pumps fail on that model/year, they may say "sure we see it all the time!"
If there is no pressure and no circulation, it is a possible water pump problem.