Over Heating??? PLEASE HELP!!!
 

Hello I’m new to your forum.
My 98 STS with the 4.6 Northstar has been over heating lately so I replaced both the water pump and thermostat over the weekend. Drove 13 miles to work this morning and half way there the gage once again shot up near the red line. It did go back down to normal after a few minutes only to climb back up again five miles latter. Does anyone have any idea what might be wrong? Thanks in advance for any help.

low coolant level or sticking thermostat, to start with.

if none of that works it may be time to rod out the radiator or replace it.