Sounds stupid but hows your catch can?
Do you have one?
If you do not have one, you are only suppose to fill the radiator just until it covers the core otherwise it will always spit out the water that has expanded.
your only problem maybe that you overfilled the radiator.
Otherwise I would remove the thermostat to make sure there is nothing blocking it. Maybe put a lower temp stat to replace it. Get a thermo heat gun ($40?) from harbor freight and check the actual temp the car is running.
Allen
Here's a novel idea, let's not throw a bunch of parts at the car hoping it will fix the problem and instead spend a little time diagnosing it first.
Life was a little easier when I was just a wrench.
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