The car has done this since I brought it home. I have removed the t stat. no viual leaks detected from pump, rad, or hoses. Swapped exhaust ( cat was definately plugged) as it wouldnt rev with the old one and does so freely now. all parts of the hoses and rad feel to be the same temp so I must guess the pump is working and checked when I topped off the coolant and burped the system. So I am now down to either I missed something or I am dead wrong with the pump or radiator. What else should I be looking for a HG? I am not blowing steam so would have to be completely internal with no oil water mix.