supermuaz

Did you ever get a definitive answer?

twh

Did you ever pull the codes from the OBD port? My water pump was complaining with error codes from the OBD port (e.g. INPA) for more than a year before it finally failed and popped up a message on the iDrive.

seanjordan20

What year/model do you have. Which temp sensor did you replace? You should have two sensors: coolant temperature sensor at cylinder head, radiator outlet temperature sensor

Katitu

I have faced the same problem with my 523i, I drove to Switzerland a couple of years ago and faced the overheating problem during my journey, I could not go over 80mph and sadly have to pull over to let a 320d overtake me. After several stops I finally reached Switzerland and immediately took my car to BMW, they quoted me 3000 Francs for a new electrical water pump, to which I was shocked and simply walked out. Long story short I drove back to London without any problems however after a year and a bit the problem came back I replaced a upper hose (warranty) and it did not fix the problem, I bought a new water pump and thermostat and all is good!

I would suspect your thermostat and water pump need replacing.

mag5qc

Have you replaced the water valve? If the coolant is constantly circulating through the heater because the water valve is NA then the coolant doesn't circulate through the radiator enough, thus staying hotter than usual. I replaced my water valve recently, it's cheap and easy to access and it cured the constant heat bellowing from the heater.

Just a thought, but your water pump, sensors and coolant should be up to spec first..