99 venture heater core and heating issues
 

Helped my father in law with his 99 venture. His radiator cracked and leaked and he didn't know so he had taken to a mechanic for a free analysis. Said radiator cracked ( I later found and confirmed), leaking water pump, and a head gasket beginning to leak 175k miles). He wanted $2200 so we decided to tackle ourselves... Took 3 days but replaced radiator, water pump, all hoses, pcv valve(was clogged), hose crumbled (posted another thread looking for the end of this hose), thermostat, flushed it, added head gasket sealer, and experienced the haunted temperature needle. It also randomly says low coolant yet the coolant sensor wire is plugged in(mounted to radiator). Odd enough its bled of all air yet it will do the darndest thing.. it will never go above midway but when the fan kicks on the temp needle drops to cold rather quickly. Anyone have any ideas why it does that? It is a new thermostat so it shouldn't be stuck open. (what a pain that was to install). Cleaned throttle body too. what else could cause the needle to drop like that? It concerns me as much as overheating. With that said the heat in the van was already poor.. you hear noise like air is blowing but pretty much nothing comes out. On AC plenty of air is heard and FELT but not on heat. I think the heater core is plugged but does anyone know how to access it? I read elsewhere you have to take the lower dash console out... where the bin is in the middle, a couple of bolts and clips. Is that true?