I noticed that at some point the cooling loop in the O2-installation stopped working. it turned out that the liquid temperature sensor is always inactive. any changes in the parameters of the sensor do not change its state. I turned debug on, removed the sensor and built it again, the cooling loop immediately correctly worked.
see picture - temp 45C, sensor "above 25C", but "inactive"
Unfortunately, I did not notice when and why the sensor broke. installation is isolated - built and forgot. I will look for save file when the installation still worked.