They can go higher.
226°F is the temp the AC cuts out.
It's not uncommon for some on the west coast or AZ to see temps in the 210°-220° all the time.
215°F is "not" overheating. The thermostat is fully open at 180°F.
When you start approaching 240°F and above is when the thermal expansion...
Also consider your thermostat.
I had about 100K on my cooling system and was experiencing overheating (226°F) when dragging a trailer and it turned out that my T-Stat was not opening all the way anymore.
I had changed out my fan clutch with an Aisin from Rockauto and it made zero difference...