i have a 96 chevy k1500 and i just did intake mainfold gaskits i did water pump i did every thing u can thing of and it was run good with new parts on and the other day i was driving to work and one of my heater core line blow out so i pulled over go the new line added coolent and ever since i see my bottem line to the rad it has coolent in it but the line is not gettin hot or hard but all the other line are hot and feel rite but that bottom one stays cool and i dont think is workin rite any body no what could be the problem with that

 

The bottom hose is the "cold" supply to the engine from the radiator.