1990 accord overheating

Did you bleed the cooling system after replacing the radiator? There should
be a bleeder valve which is near the thermostat housing.

Eric

 

My accord is overheating. the rad is brand new (was leaking). The
temperature on the dash is not registering that the car is overheating but
the rad fan won't kick in and I can hear the rad fluid boiling after the car
is turned off. could this be a bad thermostat? I can still get heat in
the car. Or could it be the fan itself causing the problem

 

Did you use the proper mixture of water and anti freeze after you
replaced the radiator?

Have you pressure tested the radiator cap?

 

I don't think at this point, "mixture of water and anti freeze" or " bleed
the cooling system", is an issue here, because even you put water only, it
should not overheat as bad as yours.

Most likely three things happened:
Your coolant level is too low
Your thermostat is bad and is kept close.
Your cooling fan is not working (either fan motor dead or thermo switch
failed)