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07-29-2021, 11:07 AM | #1 |
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The case for sacrificial anodes in your cooling system
Last August, I started a thread about sacrificial anodes in the cooling system : https://www.fordbarn.com/forum/showt...ighlight=anode. I went ahead with it, and this summer, when checking the coolant level in my '51, I removed the radiator cap and was quite surprised at the amount of deterioration it had undergone in a little less that one year. The attached pictures show the anode as removed, a new chunk of magnesium I replaced the initial one with and a shot of the deteriorated anode after I wire-brushed the crud off of it. The cooling system on this engine was scrupulously cleaned when it was installed 5 years ago. After a manual clean and flush, I ran an Evaporust process 3 times to make sure I had everything out of it.
I think the attached pictures show the value of using one of these, especially if you are running aluminum heads like I am. I am sure glad that much material was disolved from the anode, not my reworked Edmunds heads. It looks like anode replacement will become a annual task for me. The magnesium chunks were obtained from RV water heater anodes available on Amazon. I will also be flushing and replacing the anti-freeze mixture soon. |
07-29-2021, 11:31 AM | #2 |
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Re: The case for sacrificial anodes in your cooling system
tubman, Does the sacrificial material from the anode settle to the bottom tank of the radiator or stay in solution. Thanks for running your experiment and posting the results.
Thanks also for posting your first experimentation link. |
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07-29-2021, 01:12 PM | #3 | |
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Re: The case for sacrificial anodes in your cooling system
Quote:
I want to check what's in it. If I had to guess, I'd say that it pretty much stays in solution and combines with some component of the anti-freeze. When I was in high school, the only subject that caused me any trouble at all was organic chemistry, so I'm just guessing. All of this happened in less than a years elapsed time and less than 2000 miles. |
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07-29-2021, 01:34 PM | #4 |
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Re: The case for sacrificial anodes in your cooling system
Just wondering if you are using tap water or distilled water? Or, does it matter?
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07-29-2021, 01:39 PM | #5 | |
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Re: The case for sacrificial anodes in your cooling system
Quote:
I'd installed NOS heads on my '36 roadster about two years ago. At that time, I'd installed a diode in the same fashion as you. Because of your post, I'd inspected mine and found it to be nearly as new. I had to look very closely to see any type of corrasion upon it.
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07-29-2021, 02:05 PM | #6 |
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Re: The case for sacrificial anodes in your cooling system
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07-29-2021, 02:20 PM | #7 | |
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Re: The case for sacrificial anodes in your cooling system
Quote:
As to the NOS aluminum heads on your roadster, unless you know what material your diode was, you might be better of checking the heads for erosion, rather than the anode. I have seen aluminum anodes (which work if there is no other aluminum present) used to protect iron and steel. |
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07-29-2021, 02:55 PM | #8 |
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Re: The case for sacrificial anodes in your cooling system
RV water heaters are aluminum and all have an anode. Maybe 6"long and 5/8" diameter. We have to (should) change them every year and they are like swiss cheese after a year.
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07-29-2021, 03:09 PM | #9 |
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Re: The case for sacrificial anodes in your cooling system
You can get out your organic chemistry books and your studies of inorganic chemistry (a good review of them is always recommended), however this is a simple case of electrochemistry. (dig out that book and the periodic chart).
Boats use anodes for the simple reason that they live in salt water which is a terrific electrolyte and thus highly conductive. The boat sets up a great battery between the bronze propeller and the stainless shaft. The "zinc" i.e. anode is made from zinc in this case to be the anode in this battery, thus making both the prop and shaft cathodic . In a car cooling system where you have complete control over the liquid, none of this is necessary. If you use distilled water and modern "coolant" and change it periodically like you do for brake fluid, say every two to three years, you will have the results just like Kube. In the old days, distilled water was never mentioned for cooling systems. Combine that with basic "antifreeze" which was ethylene glycol and a bit of lubricants for the water pump only and you have a pending disaster. Tap water, well water or roadside pond water all have enough minerals and conductance and off PH to start a real electrical party. Old timy antifreeze had nothing to stop it. Fast forward to 21st century (actually late 20th century) and we have well developed "coolants" that have explored removing phosphates and incorporating hybrid organic acids (controlled) for corrosion protection and a million other things. Combine this with distilled water and you have a perfect liquid system that is not a home made battery, thus the electro-chemical reaction remains at zero. Use the new stuff and only distilled water. that is why it is rated for cast iron and alloy engines. The modern-modern cars take full advantage of this in having very specific coolants for their cars. i.e. G-05; G-12;G13 ;G-40 for German cars. You can test your cooling system with a good VOM to see if you have a voltage (low-less than 0.5 volts being generated ) between the liquid and the block/radiator. This sometimes works. If you have any tap water or old "antifreeze" in the system, drain and flush immediately and refill with a modern hi quality coolant and distilled water. You can then forget about it until the time to change it. |
07-29-2021, 03:11 PM | #10 |
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Re: The case for sacrificial anodes in your cooling system
This is the reason for my choice, as the RV anodes have to be magnesium if they are to protect the aluminum water heaters. Most marine anodes are zinc, which, as mentioned above, may offer no protection to aluminum at all, depending on the respective alloys used.
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07-29-2021, 03:20 PM | #11 | |
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Re: The case for sacrificial anodes in your cooling system
Quote:
I'm not pulling ahead for simple looksie. I'll be gone before the heads go bad
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07-29-2021, 03:39 PM | #12 | |
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Re: The case for sacrificial anodes in your cooling system
Quote:
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07-29-2021, 04:19 PM | #13 |
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Re: The case for sacrificial anodes in your cooling system
I run early, pump in head aluminum heads. An old timer explained to me that those water pump impellors, spinning around in the front of heads as they do, act like little turbines. Ever noticed the corrosion around that area of used 21 stud heads?
I have a daughter who, every time she'd alight from my 35, would receive a static shock. So...I need to protect my nice aluminum heads. What I do is run a 50% antifreeze mix [the green stuff], zinc anodes, numerous earth straps from block to chassis, and one of those rubber earthing straps from under car that trails on the ground. I have absolutely no electrolysis damage to the heads. Need to take extreme care whilst fitting the heads too....liberally coat each and every stud with nickel based anti seize. This will prevent electrolysis between studs and heads, which is another all too common ailment experienced by many when they try to remove heads. And, yes, to the zinc anodes, I change them about every 10 years, and they are riddled/porous, so they obviously do their job. Thing is to deal with any and all stray electrons in the system, including static.
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07-29-2021, 04:22 PM | #14 | |
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Re: The case for sacrificial anodes in your cooling system
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Crap, you make me look silly.
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07-30-2021, 08:27 AM | #15 |
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Re: The case for sacrificial anodes in your cooling system
Tubman, Perhaps you can enlighten me based on your experience.
I have read that the anode must be in contact with the metal it is protecting in order for it to actually protect properly. When you attach your anode to the radiator cap with the wire I assume the the anode touches the top of the radiator tubes and does not come in contact with the aluminum heads. QUESTION: If my thoughts are correct, how does your anode actually protect your alum heads without touching them? (PS: Chemistry was not my friend, either.) |
07-30-2021, 10:52 AM | #16 |
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Re: The case for sacrificial anodes in your cooling system
Interesting study, remember back in the day your only choice was Zerex or Prestone, the guy at advanced said there were 35 or so types, they carry around 10.
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07-30-2021, 11:13 AM | #17 |
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Re: The case for sacrificial anodes in your cooling system
You have to think of the cooling system as a very large, very weak wet cell battery. Current flows from the anode to the cathode through the electrolyte (the coolant). The anode is a reducing agent because its behavior will reduce ions at the cathode. Anode mass decreases as the reacting anode material becomes aqueous. Since electricity always wants to take the easiest path, supplying an anode of a lesser noble value protects the rest of the system. Previously, I had a "battery" with the cast iron as the cathode and the aluminum heads as the anode; now, I have one with the cast iron as the cathode and the magnesium chunk as the anode. Thus, the electrons and ions are being taken from the magnesium chunk rather than the heads. Electricity is a bully; it only picks on the weakest kid (anode). Since the electrolyte (the coolant) is involved in the whole process, only it has to be in contact with both the anode and cathode, which do not need to be in direct contact.
From some of the comments here, I get the impression that some think that the material of the anode doesn't make much difference. It does. The further apart two metals are in the Galvanic Series, the better the battery is. Remember taking an old "D" cell apart when you were a kid? The center pole was graphite, while the case was zinc. Look at the table I supplied, do a little math, and I think you can see why those old "D" cells are rated at 1.5 volts. Similarly, you will see that zinc and aluminum alloys are quite close together on the table, and will produce a much smaller voltage difference than aluminum and magnesium, thus producing a smaller current and anode erosion (less protection). Keep thinking batteries and electricity, not chemistry and some "voodoo" process. I hope this helps a bit. |
07-30-2021, 11:23 AM | #18 |
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Re: The case for sacrificial anodes in your cooling system
Where’s the best place to get a chunk of magnesium?
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07-30-2021, 11:33 AM | #19 |
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Re: The case for sacrificial anodes in your cooling system
tubman,
THANK YOU very much for clearly explaining the anode, cathode process as it relates to alum. heads.. Now, I understand. Jim |
07-30-2021, 11:35 AM | #20 |
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Re: The case for sacrificial anodes in your cooling system
Old water heaters have magnesium. Some have aluminum.
Also available here: https://www.ebay.com/sch/i.html?_fro...sacat=0&_oac=1 https://www.homedepot.com/s/water%25...20anode?NCNI-5 and Goggle provides this info. https://www.google.com/search?q=magn...hrome&ie=UTF-8 |
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