You don't fix it you replace it. Drain the radiator, replace the hose, and the thermostat, flush the system, install a 50/50 mixture of antifreeze and water, bleed the system.
Before replacing the radiator hose on a 1996 Honda Civic drain the coolant system. Once drained remove any clamps holding the hose in place and pull the unit off. Replace with new hoses.
it is by the motor on the bottom radiator hose
the lower hose
Look at the engine end of the upper radiator hose
Its on the thermostat housing by the upper radiator hose
Follow the long large radiator hose to behind the valve cover. It is not the hose that goes from the top of the radiator to the front of the engine.
It is on the lower right of the radiator and sometimes it is easier to take the lower radiator hose off.
just fallow the bottom hose from the radiator. it runs to it.
Should be in a removable housing at the engine end of the upper radiator hose
There is a sensor right where the upper radiator hose goes into the engine.
Follow the lower radiator hose into the housing, that where the thermostat is.
at the top of the lower rad hose (in housing)