So I have an 88 chevy 1500 with a 305, it was always a truck I used just to haul stuff to the dump. Recently I started driving it more often and discovered it's not only getting extremely hot but also I can't get any heat out of the heater core. I replaced the t-stat, ran water though every opening in the radiator, took the water pump off and checked the fins, replaced all the gaskets, and even tried running it without a t-stat in it. The intake and out take hoses are both getting hot along with the radiator itself but its just not cooling properly. Any ideas why it would just all of a sudden act up rather than slowly start to have issues would be helpful along with any ideas on how to fix it.