Surficial anodes in the cooling system (again)!

tubman

Well-known member
In August of 2020, 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 in July of 2021 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 picture shows the anode as removed then, and a new chunk of magnesium I replaced the initial one with. The cooling system on this engine was scrupulously cleaned when it was installed 7 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 sort of forgot about it last year, but I had occasion to check my cooling system level today. When I removed the cap, the anode I had put in new in 2021 came with it and I was shocked at what it looked like after only two years. The other picture is of that anode; remember, this is the NEW chunk in the other picture as I had discarded the eroded piece.

In light of this, I think I'll be checking and replacing them every year.
 

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Yikes! I thank you for posting this. I actually have a couple of "kits" with the anode. Most likely from the 50's.
I'd never got around to installing one but after seeing this, well, one will be installed this weekend.
I, like you will take a "before" photo and date it.

Thanks Denny :)
 
Tubman, I have been using the sacrificial, radiator cap anodes for several years now. I just replaced one with a new cap, the one I replaced was as thin as a pencil.
 
Magnesium seriously corrodes in hot aqueous media all by itself yielding hydrogen gas & milk of magnesia. So its level or rate of corrosion doesn't necessarily reflect how well it's protecting other less electropositive metals. Coolant corrosion inhibitors that passivate the surfaces of other metals like iron & aluminum are probably more effective.
 
Magnesium seriously corrodes in hot aqueous media all by itself yielding hydrogen gas & milk of magnesia. So its level or rate of corrosion doesn't necessarily reflect how well it's protecting other less electropositive metals. Coolant corrosion inhibitors that passivate the surfaces of other metals like iron & aluminum are probably more effective.
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https://www.no-rosion.com/norosioncoolant.htm

Works for me in my '34 with aluminum heads...
 
When an anode dissolves doesn't the residue fill the bottom tank and eventually hinder cooling?
 
I think it is interesting that makers of boat outdrives include sacrificial anodes attached below the water line. External verses internal systems.
 
Yep. Fairly impractical to use inhibitors in the aqueous media when it's as big as a lake, ocean or water supply. Water spiked with inhibitors like No-Rosion would prolly taste kinda funny too. 8^)
 
When an anode dissolves doesn't the residue fill the bottom tank and eventually hinder cooling?

I've searched to find the exact answer to this with no luck. Matter is changed to energy (electricity) in the process (galvanic action), so some of it just disappears. I would imagine that there may be by-products from the process (like burning gasolene produces carbon monoxide and water), but I imagine the amount is very small, and would be taken care of by periodic cooling system flushing. It certainly wouldn't be enough to cause a problem over the usual lifetime of an automobile. It may be part of the reason that radiators need attention after 10-15 years in service. I personally have not experienced any ill effects. In any case, it's a lot better that the residue you mention comes from the anode rather than your fancy aluminum heads.

I am also a fan on "No-Rosion" and bought a case of it several years ago. I quit using it after switching to sacrificial anodes, mainly because of cost.

My rationale behind using sacrificial anodes is quite simple.The ones I use are made to be used as sacrificial anodes specifically designed to protect aluminum tanks in RV water heaters. I don't think they make any of those without anodes. I guess I am just relying on the expertise and years of experience of those that are charged with making those systems work.

Over the last 65 years, I have run across many finned aluminum high-performance heads that were rendered unusable by excessive corrosion. I don't want that to happen to any of mine, given their cost and scarcity these days.
 
What, if anything, are automobile manufacturers doing now to address this problem? I have 3 modern cars with aluminum heads. The average age of them is 22 years. The mileage total is 560,000. The oldest one, 27 years old has only 127,000 miles. All were purchased with over 100k on the odometer. I do not know what happened in their "former life." In my ownership none have had a flush or a coolant renewal. I must live a charmed life for a bad, bad, boy!!!
 
What, if anything, are automobile manufacturers doing now to address this problem? I have 3 modern cars with aluminum heads. The average age of them is 22 years. The mileage total is 560,000. The oldest one, 27 years old has only 127,000 miles. All were purchased with over 100k on the odometer. I do not know what happened in their "former life." In my ownership none have had a flush or a coolant renewal. I must live a charmed life for a bad, bad, boy!!!

Haven't you noticed that all of the automobile manufacturers now have their own proprietary coolant mixtures? I just had the coolant changed on my Kia Soul to the tune of $210. They require their own coolant to maintain the warranty. Prestone is about $10 a gallon for premix and the anodes are 2 for $9.97 (which gives me 6 usable chunks). I decided it would be easier to go with good ol' green Prestone and a sacrificial anode than to decide what modern witches brew of exotic antifreeze would be best for Ford cast iron and Edmunds aluminum.
 
I just had the coolant changed on my Kia Soul to the tune of $210. They require their own coolant to maintain the warranty.

With respect Denny, I do not have that much do re mi to spend $210 on a coolant change. The only warranty I ever had was the "tail lights outta sight guarantee!" I guess I have been very lucky in the auto purchases I have made the last 61 years. Our family cost for transportation has been very minimal. I cannot remember ever calling a tow truck. I did have to walk 2 blocks home 8 years ago to get gas for my 34 Fordor with no gauge. Oh, and I hitched a ride 4 miles home in June when my 36 PU lost power to a distributor mistake I made. Maybe it's just the FORDS that are my nemesis! LOL
 
The $210 was a real surprise. Had I known, I would have figured some other way to do it. I just bring it up to show that these days, things are very different than they were when we were young. Antifreeze is no longer a generic product. I just heard from another member here that an Aston Martin requires a special coolant mix that costs $225 a gallon. Prestone is about $10 a gallon for premix and the anodes are 2 for $9.97 (which gives me 6 usable chunks). I think I'll stick with that.
 
The $210 was a real surprise. Had I known, I would have figured some other way to do it. I just bring it up to show that these days, things are very different than they were when we were young. Antifreeze is no longer a generic product. I just heard from another member here that an Aston Martin requires a special coolant mix that costs $225 a gallon. Prestone is about $10 a gallon for premix and the anodes are 2 for $9.97 (which gives me 6 usable chunks). I think I'll stick with that.

Denny, Where do you purchase the anodes? Do you just hang them from the radiator cap?

Thanks,
Pat
 
I got mine from Amazon. Here's a link : https://www.amazon.com/Magnesium-Water-2-Pack-Teflon-Included/dp/B0BG5VB23S/?tag=atomicindus08-20.

I cut them into chunks that will fit through the radiator cap opening (abou 2 1/2" long), and get 6 out of a pair that Amazon sells.

Make sure that you have a good electrical connection to the engine. I solder a tab to the rivet holding the cap together and then solder the anode lead to that tab.

Oh, I forgot. I drill and tap a 10-32 hole in the anode and use a stainless screw to attach it to the lead.
 
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In my 35, I run Prestone 50% and have fitted ZINC anodes into each bank. I change the antifreeze solution every 5 years or so, every 10 years i replace the anodes. They show some deterioration after that time. However, and most importantly, The Eddie Meyer heads are as good as the day I fitted them. An easy way to make up anodes for a 24 stud engine that has 3/8 tapped holes each side of the top water outlets in the heads [that take temperature sender units], is to get some brass 3/8 pipe plugs. They have a blind hole on the inside. tap that hole 1/4 pipe. Zinc rod is available in 1/2" dia. Cut a piece of said zinc rod about 2-2 1/2" and thread one end 1/4 pipe. Screw the zinc into the brass plug. You now have something that sorta resembles a sender unit. Fit it into the 'spare' tapped hole in the head. Externally, it just looks like a stock plug, but it's doing a vital job. One in each head will do the job nicely. Will protect those valuable heads perfectly!
 
'Magnesium seriously corrodes in hot aqueous media all by itself yielding hydrogen gas & milk of magnesia.'


I didn't know that. Looking at the periodic table, I always 'thought' Magnesium would make a better sacrificial anode, but I've only ever used zinc. And, as above, it works very well in protecting aluminum heads.
 
Re: Sacrificial anodes in the cooling system (again)!

I changed the sacrificial anode in my cooling system again today. (The last change was in August of 2023.) Here is a picture with the new anode on the left and the old one I removed on the right. These were both cut from he same RV water heater anode I bought from Amazon.
 

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