Truck Caps Used

how would i fix a coolant leak that has?
i have a 95 chevy blazer that i recently changed the radiator but not the Cap i used my old cap from my old radiator. i think that might be my problem but im not too sure. this morning i found some coolant that was leaking into the inside of my truck what can cause this to happen? and how could i fix the problem?
You have a leaking heater core or a leaking heater hose or connection. You may have to remove some of the internal dash panel to gain access. I would check the hoses first to make sure they are OK, but while you are in there, change the hoses anyway on one this old. Good luck.
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