please correct me if i'm wrong, but the number on the thermostat is the temperature that it starts to open, and to be fully open can be 10-15 degrees warmer.
example, my caravan has a 205 thermostat, but runs all day, every day, at 220 or so. never has overheating problems.
in my mind, something with a 180 thermostat will run at 195 or so, and be perfectly within design parameters of the 185 thermostat.