I have a heater core thats not putting out heat,i replaceds,heatercore,heater hoses,waterpump,3therostats,head gaskets,the electric accelwaiter under dash,the omly time i get heat[for about 3 days when i drain the coolant out] then it goes cold put a plug with a 1/4 hole in the center to slow the flow on the cross over pipe,the hose on the top is hot but the hose on the bottom is cold