engine knocking
 

I have a used engine in my z32 NA, and i was driving to work on the freeway and heard a knocking in the engine. i have reason to belive itis a rod bearing for the crankshaft going up. so i stopped driving it, and when i looked under the hood there was a TREMENDOUS amount of preasure coming out of the radiator. does that have anything to do with the rod bearings? sould i replace rods and bearings or just get a new engine? thnkx. i really need help.