paker

White89gt,
Please explain to me how coolant flow rate affects electrolysis. Do you mean cavitation? It cannot happen in heater core, at this low flow rate.

When electrolysis is caused by stray current, conductivity of coolant matters, not flow rate.

Do you still have a link for the 0.4V TSB? I would like to read it and learn about stray current information.

EDIT: I found it. Thank you.

Jbrew

There's 2 TSB's. The first TSB is a Ford screw up that should of never went into print. They actually say to ground the HC. Well, you can but, - it totally doesn't make sense since that will provide a path for strays. Unless you rout the added ground to the HC sponge. See how this doesn't make sense yet ? Your essentially providing a path then canceling it out. So yea, a fairly incredible mistake.

Ford caught the mistake (wonder if someone got fired over that) and produced a second TSB that in BOLD said , DO NOT GROUND THE HEATER CORE.

Thing is, by the time the second TSB was produced, many have copied the first one and distributed it all over the web. For that matter, I'm not even sure Ford bothered to take the first TSB down. I'd have to look to be sure.

Anyway, that's the deal with that and folks are still finding the first TSB somewhere (copied and pasted by another) before finding the second not realizing that it's bogus.

bigaaron

+1 Paker wondering if you inducing conductivity using the coolant as the medium> just a thought

Jbrew

Yea, it's a big deal in autos. Not only DC current, but AC as well from the alternator. That's why you check for AC strays as well. Not many know how to check or probe current currently in the coolant as well. You won't get an accurate reading with a normal MM probe unless you happen to have a solid copper probe. Since only copper submerged in coolant flow will net accurate readings. Thought I'd mention that since it hasn't been explained properly in the past.

You asked if electrolysis is a myth earlier. Well, the that word has been misused, misdiagnosis circumstances. Galvanic corrosion is caused by two dissimilar metals being in contact with each other, in the presence of an electrolyte. This is more often the cause of all problems in the coolant system. Electrolysis is caused by stray current that finds a path between two metals in the presence of an electrolyte. Well, you can look that up for a thorough definition lol. Anyway in most cases it's the galvanic corrosion that will destroy a heater core, specially a cheap HC replacement.

In essence what's going on is galvanic corrosion, electrolysis can enhance this at high levels but usually isn't the case and definitely isn't the root cause of HC demise. Root is the metal pieces breaking free internally due to galvanic corrosion and shot blasting the heater core. This is the reason for reducers being incorporated into the cores inlet hose. To slow down that shot blast affect.

Jbrew

Btw- the heater cores are all free from ANY metal paths. They are isolated from strays to begin with.

gkoenig

To add further detail, my original core developed a leak at 130k miles in 2011. I replaced with genuine motorcraft, cant remember what type of fluid i used but i usually buy the alluminum friendly 50/50 gallon jugs. The second heater core started leaking in 8/2016 at 140k miles. So as you can see my truck doesn't get driven a lot, maybe that has something to do with it. I spent 2 hours flushing the rusty sht out of it. It all looks fine now. Sounds like i need to remove the hc ground that i added?

Carcrazygts2

90% of the problem is ethylene glycol. It is conductive. I use CAT ELC coolant. Its formulated to reduce the effects of electrolysis. Electrolysis is common in diesels. By grounding the heater core your promoting corrosion, and the break down of aluminum internally. Along with adding a charge to the cooling system.

paker

Wow, so much information.
White89,
I was mistaken. I found a Ford bulletin that says high flow rate can cause accelerated corrosion in the heater core inlet. I didn't have the realistic understanding of coolant flow rate through heater core. As far as the coolant is not stagnant, no need to be more from corrosion inhibition stand point.

CarCrazy,
I searched internet for antifreeze (ethylene glycol) conductivity. I didn't find a specific number, but I found a chart that shows antifreeze close to deionized water. They are not much different. I don't think you need to be concerned about conductivity of conventional antifreeze. Well, it's just my opinion.

The same article shows how much conductivity increases with time. Metal adds very little. But plastics do. Nylon, teflon, polyethylene are benign, but rubber adds a lot for both solutions (deionized water and antifreeze). And we have a lot of rubber in the coolant system. Another reason why we need to replace antifreeze. I used to believe antifreeze is a lifetime deal, as manual says. After reading the article, I will start replacing antifreeze on a regular basis. Yearly may be excessive. Every few years at least. We cannot judge by the color. Conductivity seems to matter.

Your CAT-ELC has 500 ppm of nitrite and 1000 ppm of molybdate. Both will add ions and increase conductivity. I am not sure if you are gaining any from the conductivity stand point. Honestly I think your antifreeze is more conductive than conventional antifreeze. How good CAT-ELC is for corrosion protection is another matter. My best guess: with 500 ppm nitrite and 1000 ppm molybdate, it will be darn corrosion inhibitive.

Jbrew,
Thank you letting me know heater core is isolated from ground in the factory condition. Your post above opened my eyes to the complexity of coolant/stray current corrosion. I really need to study this. There must be technical articles. I will ask the library at work to get me some. I do corrosion as (a small) part of my work assignment. It will not be a waste of my 8 hours. I will report back.

Koenig,
What Jbrew wrote above on corrosion makes sense to my brain. But you are the owner and you decide what to do.

paker

I searched engineering databases for stray current in automobiles. None. Zero hit. So I asked automotive engineers. Their reply, no such thing in a regular car. Stray current seems to be a myth.

Definition of stray current is this (for those who are not familiar with this subject): Normal path of current starts with battery, copper wire, individual devices (headlamp, rely, fan motor, etc), grounding strap, chassis, and back to battery. When there is a high resistance in this all-metal path (improper grounding), current takes the shortcut through coolant and reaches back to battery. Where current leaves the metal to enter the coolant occurs corrosion.

I suppose a bad grounding strap would have 1 ohm resistance at most. If grounding is really bad and has a few ohms of resistance, current will not flow through the device and the device will not work. Coolant has a much higher resistance than a poor grounding strap. It is unlikely current leaving 1 ohm path (poor grounding) and takes the 10 ohm path (coolant). Stray current induced corrosion could be a myth. Until I find an article that says differently.

gkoenig

Definitely tough call, for me, replacing 2 heater cores in such a short period forced me to investigate some sort of voodoo corrosion. Pulling a voltage off of the liquid was legit, zero after adding the grounds, however you all know more about the science behind it.