Once again, you guys nailed it. Stuck thermostat. after like a week. POS. Thank yall again!

 

My father was about the most mechanically UN-inclined person you could meet. However, he always said to check the cheap and simple fixes first. If they work, great. If not, you eliminate one problem and can work your way up. Many years down the road, you'll qualify as an Olde Pharte and can dispense wisdom yourself.

I'll probably be in the old curmudgeon home by then gumming my gruel.

 

Well the temp gauge moves now. Still not to the middle or what i think operating temp is but it never has regularly. I think well below half is the standard running temp it seems. But still no heat. In fact the front vent have never had any air flow through them. What heat i used to have seemed to be coming from the floorboard area and there is no control for which vents are used (as far as i can tell, its a very confusing ac/heater control diagram).

 

How many miles on the engine? I think you mentioned once, but the messages are enough it can be hard to find it. If the engine has 150K or so, or is fresh and the assembly was a little sloppy, your timing might be off. I had a 3.9 once that never really got hot and when I put a new chain set in and got the timing right, it went from 130 to 200 and the heat would cook you at full blast. Fuel economy went from 16 to 23.

On the air flow, have you even been in the dash? It sounds like a blend door issue but you may also have a internal air tube unhooked.

 

About 175000 miles on the engine. Never had any rebuild, I recently discovered I had broken a line from the air cleaner (I think it’s for the gas recirculating system thing) that I have yet to reattach. I’ve never had air coming from the front vents so blend door is likely. But I used to have decentish heat coming from under the dash or somewhere. The rear heat unit has never worked nor do I understand how that whole system works. I’ve only been in the dash to screw w the cluster and install a newer radio unit.

I do know that ever since I got it and drove her across the Rockies, that I can feel outside air blowing on my legs on the highway. Like a significant amount, so there is something missing there around the firewall area.
this winter has been particularly harsh, so I really miss the heat. Also, since replacing the failed replacement fail safe stat I’ve been driving it without the doghouse on to see if I can pinpoint oil/coolant leaks and ensure the engine was warming up. Could that be a problematic in any way?
the original stat was rusted to all hell too, and then a month later the coolant was rusty again, could this clog a heater core? I’ve since drained and refilled coolant twice to try n get the rust out but when the thermostat is removed I can see there’s quite a bit of rust inside there so… I dk what effects that has or how to clean it out.

 

You have two hoses going to a rear heater core. A valve controls hot water going to it and there's a fan switch. Fairly simple but sometimes it gets quirky. I've had a van run cold air on my feet. You just have a thin wall so anything loose will let air in.

On your lack of heat, I suspect your timing chain has excessive slop. Being a van, it'll be hard to do as you can't lean over the top of the engine. To check the slop, you pull the distributor cap. Rotate the engine by hand until the mark on the balancer is lined up with the TDC line. Mark the position of the rotor. Rotate the engine backwards slowly. When the rotor starts to move, stop and measure how far it moved. If it moves more than 5 degrees or so, you have a lot of slop. If it moves more, you probably need a new timing chain. While you're ddoing that, I'd flush all the hoses with a garden hose. This includes the hoses to the rear. Otherwise, it will act as a reserve for rusty water.