i have a 98 ford escort se a realy good little car i have only had one problem with it science i have had it it needed a heater core i replaced it over a year ago dident have any more problems till now it starts to over heat only when going up big hills you can drive 100 miles no over heating till you go up big hills what could it be

 

I have a heating issue as well.

I have placed new High RPM Fans New water Pump. Thermostat Radiator Pressure good no cracks in Block or Heads also New 4 core Aluminum Radiator. Also I replace and cleaned my whole water system out. Replaced with Evans Non Water Coolant. The coolant system goes from 180 to 250 in a couple miles and keep rising. Engine is a 390 FE HP around 425 . I would be grateful for any help

Thanks Horndog

 

Need to know how you checked pressure..
If ever overheated,,,,,,,,,,,,,,,you are looking at a possible head gasket. Compression pressure is much higher than cooling system pressure tester. The heads were known for warping if overheated.