Well thank you for your effort but I can just repeat what I already wrote.
- I am getting good temps… 85-90c
- I am running INPA and ISTA (Rheingold) for live data (and many more). Google it, those are BMW OEM software and way better than any scanner or phone app, you could give it a go, but Windows laptop and OBD2 eBay or Amazon cable are needed to run those. You can do with this software literally everything people in BMW can do, if you know how to use it. And that is my problem at the moment, I don’t know how to program a new operating temperature.
- Yes I am getting an error “thermostat stuck”
And lastly, I did not change the cap. Normally it is acting only as an emergency pressure release if things go wrong, it is not a part of regular engine temperature regulating system. It is not opening and closing when you normally drive a car. It activates only in extreme situations (when the pump brakes and coolant recirculation stops, or blown head gasket, or radiator gets all smudgy inside so it limits coolant flow and so on…) and I am far from it. And OEM one is going to do its job if it comes to it. To drop the operating pressure, I used the 90-degree Tstat.
So basically, it is all good, I just need to “tell” the car that normal operating temp is not 105 but 90 degrees and the error message wont reappear and I will get my MPG back.
Thanks for your help and I hope I helped you too!