Don;t know what else to do

My 1992 Geo Storm is heating up on hills and over 70 MPH....
I changed the thermostat, flushed the radiator, and wired both fans to run all the time....but it still heats up......anyone have any suggestions on what to do next? I'm at a loss

Check the reservior and see if you see any bubbles while it is running ....you may have a leaking head gasket..leaking compression into a water jacket....Probably needs new head gasket but you can try Tightning the head bolts.