I have a 95 k1500 5.7. I purchased a new radiator online, and I cannot get the engine oil lines to screw into the radiator. They are not the quick disconnect, but the thread in type. I have tried the screw in adapters which will screw into the radiator, but the lines will not screw in. Anyone had this happen? This radiator is a single core vs a double core, maybe the problem? Anyone know of any adapters, the screw in on the lines seems bigger than the radiator threads and the adapters