boy is it hot!!!
just to clear up a few things
i beg to differ and i'll agree with you as well. if you'll read cam's post again he never mentioned boil over or losing coolant etc:
what he said was... the needle tipped the scale quite hi up at the 100 mark. so i will agree with you that the proper mixture will cause a flux in the ability to cool. however the type of coolant does matter. if you use the pgreen stuff without the corrosion proof chemicals for an aluminum system you will have a problem. and this is what i was referring to. (pls take the time to do a search on cooling system corrosion to see what i am referring to).
back in the old days 60's & 70's you could buy bottle of cooling system flush but i don't know about now if it's ok to use. even the dealers had this stuff. i think prestone sold it also.
sorry for my detour.
you didn't mention if this just started or was a problem from two years ago when you replaced the radiator.
if you have had a pressure test and found the system ok then it is sure to be a blockage somewhere. i'd still pull the thermo and replace it ... or at least test it in a pan of water. you said you can turn on your heater and get the hot air. so those lines seem ok. i'd head for the thermo.
if the thermo is ok, then you're justified pulling the radiator and getting it tested for flow. you know you might trying getting a coolant system flush unit from the pgreen people they can't be much over 10$ then you could back flush the coolant, maybe even clean out the radiator and refill with a couple of gal of your best coolant.
good luck with your problem
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