My 340 is running hot I think.. I need a sanity check.

If you don't have a recovery bottle and you fill the radiator to the top, guess what happens with the engine get hot and the water expands? Yep It goes out the overflow. You keep filling it up, it keeps pissing it out. So first you need a coolant recovery system to stop that. That also prevents air in the system when the water finds its own level and blows out the overflow. That's why old cars have rusty water because of the air in the system. Coolant recovery prevents that