I will check to see which model of thermostat I bought last time. I saved the box.
I know I'm not using BMW antifreeze. I about the high milage Prestone stuff last time. Perhaps I will switch?
I am sure that they were failing because I did test the last 2 I yanked out of the car. But my car is experiencing another likely related problem now. My heat is not working. This car demands so much of my time. And because I don't have much money right now, all I can spend is time. I was planning to goto a DIY next month and do a coolant flush and perhaps a transmission one too. Maybe that'll fix the problems.