Sacrificial Anode
 

I have always been a little concerned about corrosion of the aluminum heads that I have on a couple of engines.I thought about it, but never did anything about it because there didn't seem to be satisfactory solution. Recently, I had to put valve guide seals in my Corvette, which required pulling the heads and (aluminum) intake manifold. Quite frankly, I was surprised to see the amount of corrosion and corresponding metal loss on the manifold. I try to keep fresh antifreeze in my cars every 3 or 5 years, but I didn't like what I saw. As soon as I got the car back together, I decided it was time to do something about it.

I was looking on the internet for something, and I finally got to Amazon, and even they didn't have anything I liked. I did see however, that they had Magnesium "stink rods" for RV water heaters relatively cheap. Two 3/4" by 9 1/4" rods were $14.90 with free shipping. I ordered a couple to see what they looked like. When I got them I went to work and made the pictured device. It's just a brass washer soldered to the bottom of the radiator cap and a short length of steel chain attached to the longest chunk of the rod I could get through the radiator neck. Since the rods were magnesium, they are lower on the galvanic table, and therefore should corrode before the aluminum heads. I can make 6 sacrificial anodes out of 2 rods, and the chain, screw, and brass washer are incidentals I already had, so these came out to $2.50 each, which is quite a bit cheaper than anything out there and they have a lot more mass in the sacrificial anode.

I put one in the Corvette, too.

Re: Sacrificial Anode
 

Be cautious about putting anything in the radiator tank that can impede circulation. Just be sure that your coolant is fresh, and a can of rust preventer is added between changes. If sacrificial anodes were necessary they wouldn't be hard to find. You can check to conductivity of the coolant with a needle type meter set on high ohm scale with one lead in the radiator, the other to ground The lower the reading, the coolant is OK.

Re: Sacrificial Anode
 

"Sacrifical Diods or anodes are "Snake Oil" IMHO.

Re: Sacrificial Anode
 

When you use a sacrificial anode like the one you made does it have to literally rest on top of the inner core or is it suppose to hang free without touching the radiator?

Plus, when the anode dissolves how do you flush out the deposition particles?

Re: Sacrificial Anode
 

I have used these in my motorhome hot water heater. They do leave allot of sentiment as they dissolve which is no problem because the water heaters have a sentiment drain at the bottom of the tank.

Re: Sacrificial Anode
 

I have used the "Rad Cap" brand in my Jack Roush Mustangs and have seen them dissolve over a period of two years along with keeping my coolant change every other year, I always wonder if the water tank anodes have a specific composition versus the regular anodes designed for the cooling systems ?

Re: Sacrificial Anode
 

Innovation begins when someone tries to improve upon a system or problem. Some things work quite well, like tubman's trashcan condensers. Others may or may not. My hat is off to you tubman for trying something and for sharing it with us. Over 100 years ago the "horse crowd" thought Henry was pedaling "snake oil" too!!!

Re: Sacrificial Anode
 

I put a screw in anode in each side of the aluminum manifold. Have not taken anything apart to see how they work.

https://www.boatzincs.com/engine.html

John

Re: Sacrificial Anode
 

Thank you "34fordy" for the enlightened response. The others are quite interesting as well. I am particularly encouraged to hear about the amount of sediment that these produce; that would seem to indicate that they are working. I would think that most of the particles in the cooling system will be coming from the anode and not my aluminum heads. The maintenance on my cars includes a change of anti-freeze and a good backflushing about every 5 years, so these particles should not be a problem. If you're going to leave the anti-freeze in your car for 15-20 years, maybe one of these may not be the best solution for you.

We all know the problems with original '30's Ford aluminum heads and used finned aluminum heads. I have passed on many sets of heads that had large areas eaten away by corrosion. It IS a problem and I am trying to do my best to eliminate or at least minimize it. I haven't seen a decent set of the Edmunds heads I like so much for sale for several years now, so I'm trying to preserve what I have. If you're using cast iron heads, this is probably not required, because they are not susceptible to corrosion and, let's face it, they're a free for the asking in the community.

As to the "snake oil" comment, I can sorta relate because Chemistry was always my toughest subject in school. and why stuff like this works is a mystery to me. I have learned to trust the accepted science behind the concept, which is why I included the "Galvanic Table" in my original post.

Re: Sacrificial Anode
 

This is what I was originally going to do, but if you have a heater like in my '51, there are no spare holes in the Edmunds heads to screw them into.

Re: Sacrificial Anode
 

They are available for marine use. Outboard engines and such. I installed a bung in the top tank to make replacement easy. They do reduce corrosion of heads

Re: Sacrificial Anode
 

I needed to replace two thermostat housings over several years on a small block chevy. I purchased the radiator cap that uses a zinc anode and haven't replaced a housing since. The cap will need to be replaced soon as the zinc sacrificial anode is getting thin. No cooling issues at all. They work as far as I can see.

Re: Sacrificial Anode
 

I use the anode style that is tethered to a brass ring that is retained by the radiator cap, that way I don't have to use their style rad cap. I'd rather flush the remains of the anode sediment with a radiator flush than flush the aluminum sediment from my heads dissolving.

Re: Sacrificial Anode
 

I made this anode using a piece of magnesium inside a piece of nylon hose attached to my radiator cap.
You can see it did corrode. I also use "No=Rosion".

You can see that it did corrode. It would be nice if radiators were made with a drain plug at the very bottom of the bottom tank for washing out the anode sediment.

I find it helpful to periodically check the PH of the coolant with test strips like we used in high school chemistry class a million years ago. Or you can use a digital multimeter.

Re: Sacrificial Anode
 

It's interesting that someone displaying little knowledge of the correct phraseology involved ("Diods"), and that that someone misspells two of the descriptive words ("Sacrifical Diods") accompanying such statement, would have any credible reason to pronounce such as "Snake Oil". DD

Re: Sacrificial Anode
 

I did what I did the way I did it because I could get the biggest chunk of the least noble metal in the system that way.

Re: Sacrificial Anode
 

19Fordy touched on the subject of the PH balance in your coolant. If the PH is way off, things are going to corrode. Aren't there certain antifreeze solutions out there that are more balanced then others. I was wondering about the newer orange colored stuff that maybe it was formulated to help with the ever increasing use of aluminum in heads and blocks on the newer cars. Of course the sacrificial anodes can't hurt. Also, I'm not a chemist so what PH number should we look for.

Re: Sacrificial Anode
 

1 ton, I'm not so sure that PH has anything to do with it. My reasoning is that zinc anodes are used on boats that have outboard motors. I'm in the same boat (no pun intended) as you and don't know jack about this kind of stuff. Years ago anti freeze was anti freeze. Nowadays it is specific to every car!

Re: Sacrificial Anode
 

I put a sacrificial anode from the Boatzincs place (like John in Illinois linked) into my flathead about 10 years ago. Last year I checked it and it didn't have any corrosion or erosion on it. It is screwed into the top sender port of a stock Ford of Canada aluminum head. But, I also use antifreeze that is made for modern motors with aluminum components.

Re: Sacrificial Anode
 

Almost sounds like a pretty good plan to me, but WTH do I know? DD