I agree with the guys about trapped air in the system.
I had a 235 doing the same overheat until I pulled the thermostat and poured coolant right into the engine. It took nearly a gallon!
Once I buttoned it back up, fired it up and ran it with the rad cap off and filled it too. Once the thermostat opened (you'll know when it does by the sudden increase in coolant level) cap it and drive it.
Your car may not have an overflow tank, so don't worry about a low coolant level in the rad when it's stone cold because it will self regulate the amount of coolant it likes.
