What sort of setup are you running?
Your coolant temp would probly rise a little doing old pac but not that much. I've got a power fc which has a digital display of the water temp and the highest i've seen is about 94'C and that was highway cruising. Doing old pac, nasho and a track day has never seen it go past about 86'C so I definatly think somethings wrong.
Is your radiator fan always running? or are you running a thermo fan?
If its all a fairly stock cooling system I would get someone to at least change the coolant and if it doesn't cost to much change the thermostat too. Once you've done that it shouldn't overheat at all.