Own a 1998 Civic LX with 120K miles - The top radiator hose keeps collapsing - After I drive it and it cools down I find the hose is collapsed, but when I open the radiator cap, the hose returns to normal

I replaced the radiator cap and cleaned out the overflow container and lines to ensure it wasn't blocked - The radiator is about 3-4 years old

What else should I check?

 

change the thermostat. also bleed your water system.