70k miles, and we have noticed that the radiator fan seems to come on very quick, even when the car has been sitting overnight.

It did not behave this way, even in the summer when the temperatures were 20 degrees warmer ..

I checked the coolant level, and everything seems ok...
There are no error codes, or temperature warnings ...

Any ideas?
Should I be worried that this will cascade into another bigger problem as usual?

 

Did you ever get to the bottom of your radiator fan coming on (and staying on after shut down) even on cold starts and very short trips?
My 2010 GL350 65,000 miles has been doing the same lately.
As with yours, no error codes, coolant level looks fine, and dash readout shows temp in the 80-90 C range, which is normal.