Overheating 2004 Z4 60,000 miles. fans all work, coolant is full.

Thanks for the answer. I had it in to the dealer and they said the temperature was ok but the gauge or sending unit was bad so they replaced the sending unit. the fans work but after the change out of the sending unit it still reads it is overheating. How do you check for a bad water pump? the thermostat should be somewhat easy to change out. I just don't want to start spending money changing out everything as trial and error. I have taken it back to the dealer.

Basic... its inspecting the coolant flow back into the coolant tank. I would assume dealer had done that but who knows. The dealer should have some other opinion of what to check next if its showing a over heat condition even after changing sender. I would be interested in what tempuature does it show in the computer data stream readings. That would have to be read on a scanner that commicates with the cars computer. That temp is read by a differant sensor on the engine and is considered to be more accurate of a reading.

Interestingly, the BMW dealer says the fix they do for an overheating problem is to just replace everything. starting with the water pump and thermostats, it has two thermostats, then if that doesn't fix the problem replace the radiator. apparently this is a common problem in BMW's. I'm a little ticked that they don't have a way to measure impedance in the water flow.

I have done some research and true its a matter of elimination sometimes. You might want to seek an independant shop in your area that specializes in BMW for another opinion.