Failed Heater Core - FOUR TIMES

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Jeepwalker

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If it was, or is electrolysis then the paper-thin aluminum heater core is likely to be the first thing to go. Make sure your battery-to-engine and battery-to-body grounds are good. AND, there a very good engine-to-body ground strap (or two). There are more grounds on modern vehicles outside and inside the cab, than you can shake a stick at! They're all over the place.

And it could be you have the ground/s, but they're really rusty, from Canadian winters. Check above the L drivers' front tire (under a plastic door) for a major ground point. And back by the fuel inlet (looking from the underside of the box). Mine were real rusty. There's probably a ground strap on the exhaust-to-body too. Ground straps are just a few bucks from the parts store.
 

Sherman Bird

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If it was, or is electrolysis then the paper-thin aluminum heater core is likely to be the first thing to go. Make sure your battery-to-engine and battery-to-body grounds are good. AND, there a very good engine-to-body ground strap (or two). There are more grounds on modern vehicles outside and inside the cab, than you can shake a stick at! They're all over the place.

And it could be you have the ground/s, but they're really rusty, from Canadian winters. Check above the L drivers' front tire (under a plastic door) for a major ground point. And back by the fuel inlet (looking from the underside of the box). Mine were real rusty. There's probably a ground strap on the exhaust-to-body too. Ground straps are just a few bucks from the parts store.
One must be cautious when adding grounds in places where none were before. Case in point:

A customer of mine had a 1995 S-10 pick up with the venerable 4.3L engine with auto trans. He suffered a leaky radiator and he replace said radiator himself... Flushed out the Dex-Cool and refitted with good ole green coolant.

He came by the shop one day with the new radiator leaking and the query "can you look at it"? I observed the green coolant and admonished him to flush the system and re-install the Dex-Cool when he commenced to replace the radiator. As a comment, I implored him to add a ground wire to the radiator and the other end to the body. He did... but in Texas fashion. He decided to put a ground wire on either end of the radiator , inadvertently turning the radiator into a capacitance battery.

A short time afterwards, the radiator commenced to leaking.
He brought it by, I looked at it, removed one of the 2 added ground wires with explanation, and sent him on his way to replace the radiator again. He never had a radiator failure for the time he owned the truck.
 

Jeepwalker

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It was probably electrolysis. Rotating masses can create a magnetic field around them which can built up until a certain amount of electricity needs to find a way back to ground. If/when this occurs it's going to ground out in certain areas. Could be the main bearings (that would be bad), or the driveshaft (also bad). Could be the cooling system or other wires to the engine.

Every time a small spark jumps across the ground a small imperfection occurs. If allowed to occur long enough it can cause micro-pitting (etching) of the bearings and other metal depending on where the ground patch actually is. It's known as Electrical Discharge Machining EDM. You can look it up, there's a whole science dealing with it in industry. I could write a long post on EDM, because I/we used to deal with it with industrial motors and rotating assemblies in factories, etc. Regardless, having good grounds is key. If the radiator is the primary ground, you don't have a lot of material to work with there. Esp the solder/braze joints.
 

Jeepwalker

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I've said this before ...assuming it's not trauma which is killing the new heater cores. And the engine/body grounds are good, it could well be pH. The pH scale is logorithimic. Just a slight change from the 'ideal' pH makes a dramatic difference and can lead to wear/damage over time. And guess what a weak paper-thin item is in your system which can get easily damaged?

A change of one integer from pH of 7 to pH of 8 is 10 times more basic. A pH of 9 is 100 times more basic than 7. And here's the thing: you have mixed metals in your truck. Aluminum (heads/cooling/heating parts) are 'happy' in a certain (lower) range, and Iron is happy in a different (higher) range. The image below pretty much tells the story. "Different"...that's the key. Out of that range, metals will give up their ions. But there are a lot of ions in the iron to give up. But what about the heater core???? Not so many. However there is a very slight overlap where they are both metals are 'happy'. Finding that overlap is the trick. And by the way, copper is a more noble metal meaning it doesn't easily give up it's ions...which is one reason old copper heat exchangers (h/c-Radiators) lasted a long time. Even when the pH was out of whack. Who knew? Who cared?

PH of 8.5-9 is about the range for iron and AL and it's a narrow one. And many anti-freezes don't get you there out of the jug. Yes, they have buffers and corrosion inhibitors, but You can tweak "up" by adding a bit of Sodium Hydroxide (pure lye), or down by adding some Citric acid ..something like that. Course you have to measure it first. I would get two Digital pH testers and premixed test buffers to calibrate. Now ..most people aren't going to do this. And honestly those test strips are woefully inaccurate and don't provide enough resolution to set any pH.

In the industrial world where products cost 10's of thousands or even 100's of thousands, pH is religeously monitored and logged daily (or more) and adjusted. The potential for damage is well known. Same sort of applies to vehicles. If I was in the OP's shoes, with all the probelms, after 1) insuring the gounds were good, I'd 2) monitor and set the pH tightly and keep an eye on it. I do on my vehicles. At least to rule it out as a hidden failure point.

pH-Metal-Corrosion-scale-600x240.png
In
 
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Sherman Bird

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Do you know WHY the main ground cable on Fords go directly to the starter motor? It's to prevent gaussing during the heavy inrush of cranking current. I've seen where a well meaning, albeit lazy person put the ground up on the head instead, the cam or crank can become magnetic. Radiators are purposely isolated in rubber mounts. Problem is, the coolant/ contaminants begin to conduct electricity. Grounding one corner of a radiator doesn't harm anything. Grounding opposite ends creates an independent battery/capacitor.

The gaussing of a crank or cam on a modern engine with cam or crank sensors can cause some issues.

In conclusion, you are correct!
 
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