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Heater core leak!!!

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Old Dec 8, 2025 | 02:53 PM
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Default Heater core leak!!!

Yes, this is the inside that's fogging up and I do have that that sweet sickly smell of vaporized coolant. I just finished all that work of changing out the timing set, so the thought of pulling the dash is not sitting well with me. As a matter of fact, I refuse!!! I am going to fix this without pulling the dash. I'll let ya'll know how it goes.

 
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Old Dec 8, 2025 | 06:44 PM
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Originally Posted by Dodgevity
Yes, this is the inside that's fogging up and I do have that that sweet sickly smell of vaporized coolant. I just finished all that work of changing out the timing set, so the thought of pulling the dash is not sitting well with me. As a matter of fact, I refuse!!! I am going to fix this without pulling the dash. I'll let ya'll know how it goes.


On my old '97, I ended up removing the steering column instead of lowering it, I removed the seats for room and took the dash assembly out altogether. I was working alone and it was just easier that way. The videos show tilting the dash towards the rear and then getting in the plenum box. Trust me, removing everything made it easier. I replaced the a/c expansion core too while I was at it. Afterward, the heat would cook you and the air would freeze you. Dealing with the plenum box, I think it will be more trouble to do it in the truck. If I hadn't cleaned the cigarette smoke out of the carpet and replaced the headliner, I could have done it in a day or two. As it was, it was a 3 day job with the extra stuff I did.
 
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Old Dec 8, 2025 | 10:46 PM
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is that a dakota dash? looks odd to me

I've done several 2nd gens one third gen, my current 06 needs blend doors, but the po informed me he just replaced the heater core, so i don't even have that excuse to help me drag out the courage to pull another dash.

I don't know how the daks are, but i not the full size trucks in no way are even remotely acceptable not pulling the dash, one 2nd gen i had the dash was so gone i tried that trick, but there is absolutely no way you can get the connections outside the firewall without pulling the dash box out. I cut the pipes and ran the hoses inside the dash, something i will never do again, and would have never done the first time if i knew that's how it was going to end up

I have no issue pulling the dash back and up, worked out great for me, i always try to replace both heat and a/c while im in there
 
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Old Dec 9, 2025 | 09:55 AM
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If you do decide to replace your blend doors do it right by visiting our website www.blenddoorusa.com
 
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Old Dec 9, 2025 | 11:33 AM
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Hey, fellas. I followed through with my plan and fixed it *chemically* last night. Took maybe a half hour.

Yes, this is a Dakota as you can see in my sig. I used this stuff you see below. I know most of you will balk at this but IMHO, used judiciously, this stuff works and it's not my first go-round. I used another form of it to fix my head gasket leak roughly ten years ago and am still driving. If that's not permanent, I don't know what is, but I never had to pull the heads and I'm not losing any coolant. Even now with the heater core leak, I wasn't losing any discernibly. CRC owns K&W and they makes pretty good products overall, so I stuck with them. There are are many similar items on the market but this is the one that worked for me. If I was to say stay away from one though, it would be Bars Leaks.

Anyway, if anyone is trying this, use common sense. First, read the instructions. Second, don't use it if your heater core and radiator aren't clean. I flushed my system many years ago and have only used distilled water and coolant concentrate ever since, so I'm sure it's clean. Third... don't pour this stuff in directly (even as instructed). Drain out a bunch of your coolant, then shake up the stuff for a full minute, then mix it in with the coolant you just removed (or use fresh coolant) and pour back in WITH THE MOTOR RUNNING from cold start. Keep your motor running and do your air bleed procedure, then go for a long drive. I went on the highway, turned off overdrive (to increase my revs) and drove about 30 miles RT.

Note: The instructions say only to use half a bottle for cooling systems with three gallons or less capacity. I used maybe slightly more than half. Oh and it says I can leave it in, but I plan on draining again in a few weeks.

I'm now only smelling the coolant smell as soon as I turn on the heat. It disappears soon after, which tells me I'm smelling the remnants of the coolant. I drove in this morning with the heat off and the glass did not fog at all, which was amazing to see again. Prior to this, I was seeing the fogged windshield (as in my first pic) and coolant steam wafting up from the defog vents or out of the main vents (with heat off). I'm going on a long distance drive soon and will update further.

Previous usage....
https://dodgeforum.com/forum/2nd-gen...loss-4-7l.html

https://dodgeforum.com/forum/2nd-gen...options-3.html


https://www.stopautoleaks.com/produc...tem-stop-leak/

 

Last edited by Dodgevity; Dec 9, 2025 at 03:50 PM.
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Old Dec 9, 2025 | 10:40 PM
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Originally Posted by Dodgevity
Hey, fellas. I followed through with my plan and fixed it *chemically* last night. Took maybe a half hour.

Yes, this is a Dakota as you can see in my sig. I used this stuff you see below. I know most of you will balk at this but IMHO, used judiciously, this stuff works and it's not my first go-round. I used another form of it to fix my head gasket leak roughly ten years ago and am still driving. If that's not permanent, I don't know what is, but I never had to pull the heads and I'm not losing any coolant. Even now with the heater core leak, I wasn't losing any discernibly. CRC owns K&W and they makes pretty good products overall, so I stuck with them. There are are many similar items on the market but this is the one that worked for me. If I was to say stay away from one though, it would be Bars Leaks.

Anyway, if anyone is trying this, use common sense. First, read the instructions. Second, don't use it if your heater core and radiator aren't clean. I flushed my system many years ago and have only used distilled water and coolant concentrate ever since, so I'm sure it's clean. Third... don't pour this stuff in directly (even as instructed). Drain out a bunch of your coolant, then shake up the stuff for a full minute, then mix it in with the coolant you just removed (or use fresh coolant) and pour back in WITH THE MOTOR RUNNING from cold start. Keep your motor running and do your air bleed procedure, then go for a long drive. I went on the highway, turned off overdrive (to increase my revs) and drove about 30 miles RT.

Note: The instructions say only to use half a bottle for cooling systems with three gallons or less capacity. I used maybe slightly more than half. Oh and it says I can leave it in, but I plan on draining again in a few weeks.

I'm now only smelling the coolant smell as soon as I turn on the heat. It disappears soon after, which tells me I'm smelling the remnants of the coolant. I drove in this morning with the heat off and the glass did not fog at all, which was amazing to see again. Prior to this, I was seeing the fogged windshield (as in my first pic) and coolant steam wafting up from the defog vents or out of the main vents (with heat off). I'm going on a long distance drive soon and will update further.

Previous usage....
https://dodgeforum.com/forum/2nd-gen...loss-4-7l.html

https://dodgeforum.com/forum/2nd-gen...options-3.html


https://www.stopautoleaks.com/produc...tem-stop-leak/


If it works for you, great. I've had mixed results from these things. I used Barr's Leak to stop a leaking expansion plug, but it stopped my heater core up.
 
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Old Dec 10, 2025 | 06:15 AM
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Originally Posted by ol' grouch
If it works for you, great. I've had mixed results from these things. I used Barr's Leak to stop a leaking expansion plug, but it stopped my heater core up.
Bars Leaks is the one most likely to clog, I've heard. Never used it, but it looks like a thick liquid. The K&W pours like water.
 
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Old Dec 10, 2025 | 10:25 PM
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Originally Posted by Dodgevity
Bars Leaks is the one most likely to clog, I've heard. Never used it, but it looks like a thick liquid. The K&W pours like water.

It's a thick liquid with little ***** of compound in it. I've also used Alum-A-Seal and it's stopped small leaks, like pin hole size, on many a radiator. Barr's gets the ones that it doesn't.
 
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Old Dec 11, 2025 | 06:42 AM
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A fix in a bottle is not a fix it's a band aid. If you would have see my heater core when i removed it you would have been shocked. Most of the passages were clogged. I don't know what was put in there it was before i bought it. They did that instead of fixing the problem(leaking freeze plug). It clogged the radiator also. All the stop leaks work in a similar matter. There was an episode of Myth Busters where they used eggs to stop a leak in the radiator. It actually worked but have to wonder for how long.
 
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Old Dec 11, 2025 | 08:39 AM
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Originally Posted by Moparite
A fix in a bottle is not a fix it's a band aid. If you would have see my heater core when i removed it you would have been shocked. Most of the passages were clogged. I don't know what was put in there it was before i bought it. They did that instead of fixing the problem(leaking freeze plug). It clogged the radiator also. All the stop leaks work in a similar matter. There was an episode of Myth Busters where they used eggs to stop a leak in the radiator. It actually worked but have to wonder for how long.

Alum-A-Seal works and doesn't plug things up, but it only lasts a year or so. If I have a leak, it's cheaper in the long run to fix it correctly the first time. After I tore my '97 Dakota down, the heat and air would run you out at full blast.
 
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