BMW E60 diesel not warming up: main thermostat and other causes
E60 diesel not warming up – what is the normal operating temperature?
When the thermostats are working, the temperature while driving is around 85–90 °C, briefly a little over 90. At idle and in hard frost the temperature can drop without a fault, but if it never rises to 88 degrees, a fault is likely.
How do I tell a stuck main thermostat?
The main thermostat opens at about 88 degrees. If the temperature stays steadily at 60–80 degrees, the fault is usually there. The upper coolant hose should be warm the whole time. It is also worth checking the temperature sensor before replacing it. It is best to buy the new thermostat as an original part.
The temperature is low even though the main thermostat is new – what could be the cause?
The automatic gearbox oil heat exchanger has its own thermostat, which directs coolant past the main thermostat. If the temperature stays below 80 degrees even after the thermostats have been replaced, replacing the heat exchanger has raised the temperature to about 88–90 degrees.