92 bravada overheating help!

i have replaced the radiator and water pump..still overheats.thers no water in the oil so no head crack.i'm stumped.it heats up immediately to 210 and it takes about 10 miles to overheat and spew antifreeze out of the cap.there is no leaks at all.please help

No water in oil does not say head or head gasket can be bad or good.
Have you replace or checked the thermo stat?

yes i have replaced the thermostat.i now notice the return line for the heater core is boiling?i have no ideas about that .the heater core is workin fine with no leaks.

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have you gotten your block flushed? somtimes cheap antifreeze gums up and blocks vital coolant highways. get it flushed professionally if you haven't already.