If you have replaced your heater core and you are experiencing the same problem again, ck your alluminum heater core linesets for a grove that is a defect during tube rolling or manufacturing. I replace heater core in my 2001 Dakota and a couple of months later I had the same symptoms again. Windsheild fogging up and the sweet aroma of glycol or antifreeze. I pulled the dash and heater box, in three hours this time compared to day and a half the first time. Opened up the heater box and to my surprise found very little antifreeze. I put heater core in a tank of water and pressurized to 30 PSI. No bubbles, no leaks. I still had first core in the shop, so out of curiosity I pressure tested the same way and low and behold the old one had no leaks. I got to looking for a trail of green under the floormats and found that the antifreeze was coming in from the lines going through the fire wall. The joint outside between rubber hose and alluminum was leaking and the foam gasket for the heater core lines was acting as a wick. The problem is the lines have a slite grove in them. If the rubber or some type of sealant is not used to fill this void they will leak. On the very end of the lines there is a swedged end and the in goes for a couple of inchs and it has another swedge that the lines are secured to the heater box with a plastic type clamp. When I reassembled I put a little silicone, careful not to get in the openings, and put the hoses on. Then I used two narrow clamps on each hose. One directly over the outer swedge and one on the flat part toward the fire wall. Also was careful not to push rubber hoses up to tight against the firewall. As an added measure of not allowing an exterior leak to get inside, before installing rubber hoses, I masked off one half inch around the foam gasket and opening for the heater core lines and siliconed the entire area, also mask off your lines. Use black silicone. When dry take a razor blade and follow tape line and remove tape. This will leave a nice neat water tight seal, that looks factory.
One more thing allow all to dry and set up before leak testing. I am comfident that there are many out there who are changing cores when it is this same problem. After removing the dash two times this is a simple repair. So far so good with dry windsheild and no smell.
I hope this will help some other soul from changing core multiple times when this could be your problem. By using two thin clamps, you can rotate them so the flat part of the clamp where the screw is, are at diff. times on the clock if that makes sense This allows the same amount of pressue on the hose all the way around, which will fill any low spots in your alluminum lines. The groove I found in my lines ran with the lines from swedge to swedge, the anti freeze was following the small channel to the foam gasket. What put me on to this was, I remembered when I replaced intake gasket, I went ahead and replaced water pump and all hoses including the heater hoses, and I had a problem then Dec 2009 with getting heater hoses to seal.
I would love to hear feed back and maybe others who have discovered this flaw. Dodge manufaturer flaw I might add, that the consumer is stuck with figuring out.
Have a great day.
As Paul Harvey would say, Now you know the rest of the story.
Darrell

 

im having a similar problem, it dosent blow hot at all and i get a wiff of antifreeze when first starting it up. i changed thermostate and didnt change anything which leads me to think its the heater core.

my carpets are perfectly dry though

 

If you have no heat you have no water/antifreeze flow through your core or your airflow is not being directed across the core or possibly both. To ck flow feel the inlet line to core under the hood at the firewall. This will be the top line. After the truck has warmed up ck your temp gauge and it should be in the middle or normal operating temp. range. Feel the bottom line. Both lines should be hot or warm if you have water flow. If not ck. to see if you have any control valve in the heater lines that may be shutting off flow. If no valves are shut and you have no flow, try backflushing the core with water hose. When water has cooled, bypass core by taking both hoses off and use a 1/2 piece of pipe to hook both hoses together. This will save time in not having to drain the cooling system. Go to hardware store and get a 1/2 female garden hose end and pick up about two or three feet of heater hose the same size as on your truck. Hook this to bottom line on core and turn water hose on slowly. You may want to attach a short piece of hose to top line on heater core and drop this end in a bucket. Then you can see if or what comes out of you core.
To be sure on your carpet, pull the carpet back under the dash around where the lines come through. Sometimes antifreeze can leak under the foam on the back of the carpet and the carpet will feel dry. Your antifreeze smell could possibly be coming from somewhere else. I would not want to change core unless absolutely necessary. If your truck water temp was heating up to normal before, the t-stat was not bad. Dakotas are slow by nature in heating up.
Hope this helps and good luck
Darrell

 

im probabley not going to even touch it, winter hasnt been to bad here so its not a problem right now. its a single cab and i have subwoofers hooked up so itll be tight as hell working