Failed Heater Core - FOUR TIMES

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bradlogan

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Hello,
New to forum, desperate for some insight.
I have a 2016 1500, Hemi 5.7. I bought it in 2020. Purchased with about 115,00 KM / 71,000 miles. it has 240,000km/ 149,000miles. The truck and I are in a love/hate relationship. Here is the latest issue. yesterday, the heater core has failed for the FOURTH TIME since January 2023. yup, less than 6 months. my local garage has dealt with it each time (they have just a hate relationship with my truck). background. my water pump started leaking during winter of 2021/2022, but because was laid off due to covid I couldn't fix it. I had heat, barely, so just drove the truck only when needed. I finally was able to replace the water pump in Jan 2023. Did myself, had no known issues, to me anyways, when I replaced it. About two weeks after replacing the water pump, the heater core went, so late Jan 2023, was the first time. Took it to the garage as it was too big of project that I wanted to do. They replaced with after market. Later Feb 2023, it failed and they replaced with different after market. April 2023, it failed again, they replaced with a dodge heater core. And now July 2023, THAT dodge heater core has just failed. They are at a loss as to why or how it could fail so many times. Obviously they are getting tired of doing this work for free, and I'm getting tired of taking it to them.

Any theories or suggestions on what we are missing that could result in four heater cores failing in short order? The heater core is not rocket science, but good grief something is "chewing them up".

Thank you!
 

Burla

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Bad fuse or ground, do you have high water pressure? Maybe the new water pump? All the fails are after the water pump install, check water psi.
 
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bradlogan

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That’s interesting, had not realized that one. Thanks!
 

Jeepwalker

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Has any one cut one of these heater core's apart to see what's going on inside? Are they leaking at the braze joints (or where?)? What's your water treatment look like?

Some possibilities could include:
1) pH totally out of whack. High ph eats aluminum. Guess what the thinnest aluminum part is? It doesn't mean it will eat a hole, all that's necessary is eating around a braze joint. Are they reusing your old coolant every time? Ask them to do a pH test. That should solve this question. Remember, coolant contains components to help reduce corrosivity, even if the pH measured is slightly outside of the 'safe' range. pH strips are terrible in accuracy, which is what most shops use. A good digital meter is much better...but must be properly calibrated or checked against a known set of pH buffers, of different known pH levels. Then you know your meter is reading properly. See charts below.
2) Bad engine ground and somehow the heater core has become the anode?
3) Too much pressure (Per Burla above). But to add ....it high pressure can be caused by a bad headgasket too. A headgasket can be 'semi-bad' for quite a while prior to a full-on white-out! LOL. How does the upper radiator hose feel when the truck is warm? Do you hear gurgling in the AM when you go to drive the truck? Do you smell combustion through the radiator? Bubbles in the coolant at higher rpm's.
4) 4 bad heater cores in a row. Unlikely, but certainly a possibility. Maybe there was a bad run of H/C's where braze joints are weak. Or the way they are packaged, they take too much abuse via shipping which weakens the inlet pipe braze joint.
5) Incompetent dealer tech getting 'rough' with the h/c during install.


These two charts say a lot: Aluminum is low nobility ...meaning it pretty freely gives up it's electrons compared to many metals (like Copper). And 2) Too high of a pH is good for iron, but not for Aluminum. Meaning a high pH will cause AL corrosion. In a mixed Iron/Aluminum system, a pH of aroud (or just under) 9.0 is within the narrow window for both metals. Copper core heater cores (like back in the old days), copper doesn't readily give up it's electrons (as easily). It could withstand coolant neglect a lot more.

Nobility of common metals.png

pH-Metal-Corrosion-scale-600x240.png
 
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Jeepwalker

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I checked my Dodge Ram's coolant pH yesterday and it measured 8.0. That's down from where it was last fall. It' a safe environment the aluminum heater core and components, but I need to bump it up closer to 8.8 to satisfy the iron components (engine ..lol).

Ironically my other vehicles pH haven't changed.
 
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bradlogan

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Bad fuse or ground, do you have high water pressure? Maybe the new water pump? All the fails are after the water pump install, check water psi.
As for the fuse, can you explain? I didn’t think the core had a fuse (and how would that result in coolant pouring out?).
 

Jeepwalker

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So, is it the Hose? Or a H/C braze joint on a fitting near the hose?
 

Burla

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As for the fuse, can you explain? I didn’t think the core had a fuse (and how would that result in coolant pouring out?).
One would have to mention coolant was flowing out to rule that out, now that it is mentioned, it wouldnt be that.
 
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