What should the engine coolant temperature be?




I am looking at buying a friends 2006 A180 CDi. It has travelled around 137,000 kilometres.
A recent drive in the car saw the engine water temp get to a max of 80 degrees, and at times was lower than that.
I was under the impression that most Mercedes run around the 90/100 degrees range.
I have owned 4 W211 E class Mercedes before and that is where they all sat (E350, 500, 55 AMG and 320 CDi)
Is it possible that my thermostat might be sticking open too far, I had this issue in my E320 CDi till I replaced the thermostat.
Can anyone assist please?
Cheers,
Graeme


