Toyota Repair: 4runner over heating, radiator cap, slow leak

Question
My 90 4runner 22re has had a slow leak somewhere in cooling system, hasn't been a problem. After a weekend in the mountains and snow the water pump blew out draining all the coolant and over heating engine. Water pump was replaced next day but after driving a while temp started climbing. I ran motor with the radiator cap off and water was shooting out,so I replaced thermostat and cooling system seemed normal but temp started climbing right away and water boiled. Now it's beyond me, help.  

Answer
The engine probably has a leaking headgasket due to the overheating, my recommendation is to have it checked for that possibility, this can be done at most repair shops but I recommend going to a toyota dealer to have the test done. If the test result is good replace the radiator it is probably clogged up.