the leak will need to be sourced and r/r'd:
>usual suspects: hoses, clamps, H20 pump, rad, overflow resovoir/hose, cap, heater core, etc.
most likely a good idea for a '87 car to have all the entire cooling system reviewed/ serviced/ maintained: hoses and clamps, thermostat, H20 pump, belts, etc. >>
hope this helps