C350 CDI om642 correct engine temperature?

[philnewmerc]

Hi all. My new to me v6 diesel has an engine temp around 80 in town and about 67 on motorways. Is that normal?
My first fill up of 70% modest motorway driving gave 34 mpg, which is a long way from 47 it is supposed to - yes I know it wouldn't do that but I thought 40 would be realistic. maybe not? Or is this a temp issue?
Thanks!
P

 

[OneForTheRoad]

90. Definitely won't help.

 

[sautah]

Running cold. Thermostat stuck open I would say.

Good opportunity do do the belts/ idlers etc and a coolant flush.