Who did it? Did they put weatherstripping around it before they put it in? If not the cold air will go right around the core. If this issue started about the same time it was replaced it could be the reason.

 

It did this before the Heater core was done and the new one didnt come with one. Ive talked to a few shops and they are saying blend door seal? Does that make sense ? Where is the seal on the blend door ?

 

Here’s what I did to mine
https://dodgeforum.com/forum/2nd-gen...ml#post3510950

 

Thank you for this ! I have no idea what a blend door looked like. So all you did was replace the foam gasket and you got your heat back? Also were you having the same symptoms as I am? And did you have to completely remove the dash? When I did the heater core I had just enough room to get my hands in there. I have no idea how you'd be able to remove the whole thing out of the truck?

 

You have to lower the steering column, Remove all the screws on the dash(by the windshield) then there are two bolts on each side of the dash down the bottom. I put ratchet strap on the dash to lift it up so i could work then remove the hvac unit. This is a lot to go threw if you are still not sure if that's the issue. What happens when you put the dial on recirculate and blow the air out of the vents? This will only allow the air in the cab to go into the hvac unit rather than the -30 air..

 

I originally had no heat… the deteriorating foam had the door stuck… eventually it broke free and foam crumbs blew out the vents.
My dash was also cracked so I did a complete dash rebuild… I was doing everything while it was out.

 

Just a update guys. I rented a rad cap pressure tool and set the pressure to 1 pound above the 16 pound rad cap rating. ( so 17 pounds ) 5 minutes later I'm getting a leak. It's coming from the bottom of the water pump and possibly above it. Does that mean this water pump is toast ? It has only 50xxx on it. Can this be part of the reason my heat isn't good ??

 

This is a great idea and im going to try it ! I went and rented a rad cap pressure tool and discovered im getting a leak from the water pump. Im assuming its coming from the weep hole. Does this mean the pump is toast ? And Part of the reason my heat sucks ?

 

I did what you suggested and rented that tool. I have a 16 pound rad cap and pressured it at 17. 5 minutes later discovered a leak and lost some pressure. It's leaking from the bottom of the water pump in thr centre. I'm assuming that's the weep hole ? Does this mean the pump is toast and its the reason why my heat sucks ?

the circle is bottom of the pump where the leak was coming from.

 

Might be from the weep hole in the water pump. (yep, that means pump is bad....) There is also a bypass hose cleverly concealed under the a/c compressor the might be leaking... but, I would think you would see that more down the sides of the timing cover.