I have a 97 k1500 with a 350 vortec. So recently it’s gotten cold and I wanted my heater but it wasn’t workin I just picked this truck up a month ago. The previous owner had installed a valve for whatever reason and it closed on the heater core inlet hose and I opened the valve and coolant went everywhere leaking out the valve so I changed this hose let the truck get completely warm and turned the heat on. It blew hotter on hot than it did on cold but still not enough to be considered heat. I don’t think the heater core is bad Bc it doesn’t leak any on my floorboard. Any suggestions???