my nova runs hot 210 and some time gets up to 240
A) Bad thermostat.
B) Bad Radiator, If the radiator is the original it is very, very likely full of rust and scale. If newer you could remove it and take it to a radiator shop and have it leak and flow tested.
C) bad water pump.
D) Blown head gasket.
A couple of other cheap possibilities - loose or worn out fan belt, and bad radiator cap (but that’s doubtful if you’re getting to 240F).
If you take the cap off and look in the radiator, is it clean, or are there deposits?