Screwed up on coolant flush. Had run at about 212*F average winter and now with warmer weather since purchasing about 5-6k miles ago. Previous owner had green in it.
Bought new thermostat, gasket, and 3 gal of Zerex red coolant. Drained through radiator, then yanked lower hose, filled with distilled and ran for 15 min, drained, repeated same distilled water flush again and drained (was basically clear at this point). Went to yank thermostat, and one bolt wouldn't free... rounded it a little even. So, crap, filled with my Zerex and went for a drive.
Hit 217*F now romping on interstate where I was always 212*F (all things equal)... coolant overflowing from reservoir. Got up on a curb and bled system all over again, probably 20 minutes of idling and trying to get radiator to take more coolant. Hit 217*F again. Repeated this process for 30 minutes on another curb, hit 217*F once again.
Weird is that it cools down quicker now, like cruising around town it's lower (about 204*F) and will actually drop to like 199 at a light.. but once I open it up and it exceeds 212 it'll continue to get hotter at stop lights.
Maybe I got some gunk in my thermostat now, but damn... how in the hell am I going to get it off with an increasingly rounded bolt, and then lose $30 of new coolant? Ahg!