Car running too cold

A 180 F T-stat shouldn't run 160 F. It will run slightly lower than the stamped set-point in the winter, and slightly hotter in summer, but not that different. I had that in my 1984 M-B. I tested the T-stat in a pot of water and seemed to work OK, then went further using an IR gun, mercury thermometer, and other T-stats. Turned out it opened slightly early and responded more sluggishly. Changing the T-stat ran at the proper 82 C on the dash, when it had run 60 C. Mileage improved after too. Of course, verify your dash reading first.