On modern cars, the following cooperatively working devices achieve temperature control:
Radiator cooling fan
Variable displacement pump
DME activates all of them when the coolant temperature approaches 108-110 degrees. Alltogether, and not each separately. In contrast to the classic cold thermostat: when it is open, the cooling fan is off, and there is no point in this (purely academic case, in practice, a cold thermostat on “hot” firmware is really useful).
If we talk about good cold firmware, then it must correctly manage all the listed components. In other words, chip makers must intervene in the operation of important operating modes of engine components. Therefore, I have great doubts about the existence of such a firmware.
Now about the BMW engine coolant temperature corrector. As I already wrote, all engine temperature control mechanisms are activated when the coolant reaches the upper temperature threshold. According to the algorithm specified by the manufacturer in the DME. The thermostat corrector only shifts this threshold down by 12-15 degrees and does not affect anything else or interfere with the operation of other devices.
The point is this: increasing the transmitted temperature from the sensor to the system within 15 degrees. What does it do? Cooling fan turns on; electric pump works more intensively (if you have such option). The temperature seen by the system is corrected (shift upwards by an average of 15 degrees). Now, through the hidden menu, the average temperature is 110 degrees, but in fact, it is 95.
When the temperature reaches 93-95 degrees (in my case), this device corrects sensor readings by 12-15 degrees. In the 7th test, you can see a surge in readings. Starting from a certain point, we see that the temperature is 12-15 degrees higher than it actually is. The entire cooling system starts to operate at a lower temperature and operates normally. More information can be found on the internet.
I think this option is excellent, and I see no arguments against it. This is a ready-made, tested product for good money. Surely, this can be implemented through an engine firmware update, but not all engines have it. For myself, I chose this method, it seems to me simpler and more practical, and the installation of the device takes 15 minutes. You can remove the device at any time by yourself.
I’ve been driving with the BMW engine coolant temperature corrector for about 2 months now. No problems at all. The oil temperature dropped and in urban conditions, it is about 100 degrees Celsius. I don’t see real readings of the coolant temperature, apparently, it dropped by the same 12-15 degrees.