alright so here's what I did. my 96 xjs heater sucked. I flushed the core did away with the control valve and ran a bit of water through the pump thru the whole system to make sure it circulated. come to find out the problem was the vent on the blower. I zip tied it open and the heater worked great. the next day I started it waited for it to warm up and it didn't. it overheated. I changed both the water pump and the thermostat and ran the return line of the pump into the suction still overheats. it has plenty of coolant just kinda stuck. maybe the water froze somewhere? its been really cold where im at. any ideas? im gonna get at it wednesday im out of town now just need an idea here. help!